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TUFTS   UNIVERSITY   LIBRARIES 


3  9090  014  531    723 


I 


Webster  Family  Library  of  Veterinary  Medicine 
Cummings  Sciiool  of  Veterinaiv  Medicine  at 
tutts  University 
■200  VVestboro  Road 
Nortli  Grafton,  MA  01536 


VADE   MECUM 


OF 


EQUINE   ANATOMY. 


FOR  THE  USE  OF  ADVANCED  STUDENTS 
AND   VETERINARY  SURGEONS. 


BY 


A.  LIAUTARD.  M.D.,V,S. 


5    T    ik/IJ 


Pro/esso7'  of   Comparative  Anatorny  to  the  American 
Veterinary  College,  Etc.,  Etc. 


NEW  YORK : 
Published  at  the  American  Vetebinary  College,  141  W.  Fifty-fourth  St. 

1879. 


Press  of 

CHAUNCEY  HOLT, 

119  and  121  Nassau  Street, 

New  York. 


COPYKIGHT,  1879, 
BY 

A.  LIAUTARD,  M.D.,V.S. 


TO 

GEORGE  FLEMING,  F.E.C.V.S. 

FOR     HIS    UNriRING    EFFORTS    IX     ADVANCING    THE    CAUSE    OF 

VETERINARY    SCIENCE,    THIS    LITTLE    VOLUME 

IS  RESPECTFULLY  DEDICATED,  BY 

THE   AUTHOR. 


CONTENTS 


PAGE. 

IntPwOductoey 9 

Osteology  (Generalities) 10 

Myology,  "         U 

Syjjdesmology,     "         12 

Splanchnology,  "         14 

Angeiology,  "         15 

Neurology,  "         16 

EXTREMITIES. 

AntePvIor  Leg 17 

Osteology 17 

Syndesmolog Y 21 

Myology 24 

Angeiology 31 

Neurology 35 

Appendages  of  the  Digital  Region 40 

Posterior  Leg 45 

Osteology ! 45 

Syndesmology 50 

Myology 52 

Angeiology 59 

Neurology 63 

HEAD. 

Osteology 67 

Syndesmology 74 

Myology 74 

Splanchnology 77 

Nasal  Cavities 77 

Buccal  Cavity 78 


CONTENTS. 

PAGE. 

Eye 84 

Ear 88 

Cranium 91 

Enceplialon 92 

Pharynx 97 

Larynx  98 

Salivary  Glands 100 

Angeiology 103 

Netjeology 109 


TRUNK. 

Osteology 117 

Neueology 118 

NECK. 

Osteology : 119 

S  yndesmolog  Y 120 

Myology 121 

Splanchnology 126 

Trachea 126 

(Esophagus 127 

Thyroid  Gland 128 

Angeiology ^ 128 

Neueology 129 

THORAX. 

Osteology 131 

Syndesmology 134 

Myology 1 35 

Splanchnology 1 39 

Pleura 139 

Bronchia 139 

Lungs , 140 

Heart 141 

Angeiology 144 

Neueology 150 


CONTENTS. 

PAGE. 

DIAPHRAGMATIC  REGION. 

Myology 151 

Angeiolog  y 151 

ABDOMEN. 

Osteology 152 

s  yndesmology 152 

Myology 153 

Splanchnology 157 

Peritoneum 157 

Stomach 158 

Liver 159 

Spleen 160 

Pancreas 161 

Kidneys 162 

Ureters •. 162 

Ovaries 163 

Oviducts 163 

Uterus 163 

Intestines 164 

Angeiology 167 

Neurology 174 


PELVIS. 

Osteology 176 

s  yndesmology 177 

Myology I77 

Splanchnology I77 

Rectum I77 

Anus .'...178 

Bladder ^ 178 

Vagina I79 

Vulva 179 

Angeiology 179 

Neueology 183 


CONTENTS. 

PAGE. 

CAUDAL  REGION. 

Osteology 183 

s  ynde8m0l0g  y 183 

Myology 183 

Angeiology 184 

Neurology 184 

APPENDIX. 

Genital  Organs  of  Male 185 

Female 190 

Table  of  Arterial  Subdivision 192 

Bones,  (centers  of  ossificationj 197 


PREFACE 


In  presenting  to  the  veterinary  profession  of  America  tliis  Vade 
Mecum  of  Equine  Anatomy,  I  fully  appreciate  the  difficulties 
whi  ch  must  beset  its  introduction,  by  reason  of  the  unbounded 
popularity  of  Chauveau's  and  Fleming's  excellent  works  upon 
the  subject,  and  it  is  not  issued  with  the  hope  that  they  shall 
thereby  be  supplanted,  but  that  it  may  fill  a  vacancy  long  existing. 

During  the  years  I  have  devoted  to  the  teacliing  of  veterinary 
anatomy,  the  fact  has  grown  apace,  that  advanced  students,  and 
practitioners  as  well,  have  felt  the  need  of  an  abridged  work  in 
which  thej  could,  without  the  loss  of  time,  review  the  descriptive 
anatomy  of  a  region. 

It  was  in  view  of  this  want  that  I  assumed  the  responsibility 
of  attempting  to  supply  the  deficiency,  and  while  the  reader  will 
find  the  text  of  Chauveau  and  Fleming  has  been  closely  followed, 
there  is  presented  an  arrangement  of  the  subject-matter  correspond- 
ing to  my  adopted  mode  of  lecturing. 

If  then,  this  little  volume  shall  prove  a  saving  of  time  to  students 
reviewing  their  studies,  and  serve  to  refresh  the  memory  of  the 
busy  practitioner  who  is  about  to  operate,  it  will  have  accom- 
plished all  the  author  could  desire. 

A.    LIAUTARD. 

New  York.   N'ov.  1878. 


VADE  MECUM 

OK 

EQUINE   ANATOMY. 


CHAPTER  I. 


INTTRODUCTORY. 

Definition. — Anatomy  is  the  Science  of  Structure, 

Division. — Descriptive,  General,  Microscopical,  Hu- 
man, Yeterinary,  Comparative,  Surgical,  Topographi- 
cal, Vegetable,  Animal,  Special. 

Organs. — Are  the  instruments  of  life. 

Apparatus. — A  collection  of  organs  for  the  perform- 
ance of  one  function. 

Division: — Apparatus  of  Locomotion,  Digestion, 
Respiration,  Circulation,  Innervation,  Urinary  Depura- 
tion, of  different  Senses,  and  of  Generation. 


10  EQUINE    ANATOMY. 

OSTEOLOGY. 

The  study  of  bones,  or  passive  organs  of  locomo- 
tion . 

Skeleton. — Comprises  all  the  bones  of  the  body; 
natural,  if  articulated  with  ligaments ;  artificial,  if  by 
wire  or  other  agents. 

Division  : — Trunk  and  extremities. 

Trunk. — Includes  the  vertebral  column,  with  the 
head,  ribs  and  sternum. 

Extremities — Are  divided  into  anterior,  or  thoracic, 
and  posterior,  or  abdominal. 

The  Anterior — Is  divided  into  shoulder,  arm,  fore- 
arm and  digital  region. 

The  Posterior — Into  hip,  thigh,  leg,  and  digital 
region. 

Bones. — Nomenclature. — Has  no  base;  from  tlieir 
form,  as  theperone;  their  resemblance  to  other  objects, 
the  tibia;  their  position,  the  ribs;  their  use,  the  frontal 
or  parietal. 

Situation. — Kelative  1°  to  the  median  line :  single  or 
symmetrical,  as  the  vertebrae,  and  double  orasymetrical, 
the  bones  of  the  limbs;  or  2°  to  other  parts  of  the  body, 
the  radius  is  in  front  of  the  cubitus. 

Direction. — Horizontal,  vertical  or  oblique. 

Form — is  absolute :  long  bone,  as  the  femur ;  flat. 


INTRODUCTORY.  11 

as  the  scapula ;  short,  as  the  patella ;  elongated,  as  the 
ribs  ;  or — 

Kelative  :    triangular,  as    the  scapula ;    prismatic, 
as  the  tibia. 

[     r  r  (condyles; 

M        .•^,  i„,    ]  diartlirodial:   -^trochlea: 
I  I  articular;  ^  (facettes  and  head; 

[^synartlirodial;  denticulated; 


exteexal 
Peculiarities. 


s  ^ 


,.  (tuberosities,    crest, 

_^^^^^'tic.; -^     lines,  &c. 

S  (articular; glenoid,  cotyloid; 

S  -<  (groove,  fissures, 

g  (nonartic; -,     fossae,  notches, 

(    foramen. 

Structure. — Tissue  proper,  Haversian  canals,  bone 
cells,  compact  and  spongy  tissue,  animal  and  earthy 
matter ;  periosteum,  marrow,  blood-vessels,  nerves  and 
lymphatics. 

Development. — Mucous  or  gelatinous  matter,  car- 
tilagiiie,  bone.    Centres  of  ossirication. 

MYOLOGY. 

The  study  of  muscles  or  active  organs  of  locomotion. 

Division. — Into  those  of  organic  life  or  internal 
muscles,  and  of  animal  life  or  external  muscles. 

Size. — They  are  large,  small  and  very  small. 

Situation. — With  the  median  line  or  the  other 
organs. 

Form. — Long,  fusiform,  conical,  cylindrical,  penni- 


12  EQUINE  ANATOMY. 

form,  wide,  elliptical,  quadrilateral,  triangular,  etc. 

Direction. — Varies  :  according  to  their  axis,  rectilin- 
ear or  curvilinear  ;  according  to  the  plumb-line,  vertical 
or  horizontal ;  according  to  bony  levers,  parallel  or 
oblique. 

Attachments. — Are  fixed  or  origin,  and  movable 
or  insertion. 

Connections. — Are  with  the  skin,  bones,  muscles  or 
other  organs. 

Strcctdee. — Red  and  white  fibres,  cellular  tissue, 
vessels  and  nerves. 

Uses. — Flexors,  extensors,  abductors,  adductors  or 
rotators. 

Annexes. — Such  as  aponeurosis  of  contention,  serous 
bursse,  synovial  sheaths. 

S¥i\OESMOLOGY. 

The  study  of  joints  or  articulations. 

Division. — Diarthrodial,  or  movable  ;  synarthrodial, 
or  immovable  ;  amphiarthrodial,  or  mixed. 

Diarthrodial  Joint. — Offers  for  study, — 

Articular  surfaces — Facettes,  head,  condyles,  etc. 

Cartilages  of  covering — Which  are  smooth  and 
shining. 

Complementary  cartilages — As  the  meniscus. 

Ligaments. — White,  being  peripheric,  or  capsular 


INTRODUCTORY.  13 

and  funicular,  as  the  lateral  and  interosseous  ;  or  yellow, 
all  peripheric. 

Synovial  capsula. — A  serous  membrane  secreting 
tlie  synovia. 

Motions. — Seven  :  simple  gliding,  flexion,  extension, 
abduction,  adduction,  rotation  and  circumduction. 

Classification. — Enarthrosis,  with  all  motions,  as 
the  coxo-femoral  joint ;  angular  ginglimus,  or  perfect 
hinoje,  with  flexion  and  extension,  as  the  tibio-tarsal 
joint ;  condyloid  or  imperfect  hinge,  with  flexion, 
extension  and  rotation,  as  the  femoro-tibial ;  trochoid 
or  lateral  ginglymus,  with  rotation,  as  the  axoido-atloid ; 
arthrodia,  with  simple  gliding,  as  the  carpo  metacarpal. 

Nomenclature. — Made  from  the  bony  pieces  which 
form  them. 

Synarthrodia!  Joint. — Articular  surfaces,  irregu- 
lar, denticulated,  and  on  the  borders  or  faces  of  flat 
bones. 

Means  of  union. — Interosseous  ligaments  and 
periosteum. 

Motions, — Very  limited  in  young,  and  absent  in 
old  subjects. 

Classification. — Sutura  vera,  or  dentata,  as  the 
pieces  of  frontal  bone ;  sutura  squammosa,  as  the 
parieto-temporal  joint ;  sutura  harmonia,  as  the  occi- 
pito-temporal  joint ;   schindylesis,  mortise-like,  as  the 


14  EQUINE  ANATOMY. 

submaxillary  and  nasal  bones  ;  gomphosis,  as  the  teeth. 

Amphiarthrodial  Joint. — Articular  surfaces  are 
often  smooth  like  the  diarthrodial,  or  rono-h  and  cov- 
ered  by  cartilage. 

Means  of  union. — Fibro-cartilages  or  menisci,  and 
peripheric  ligaments. 

Motions. — Limited,  and  varying  with  the  thickness 
of  cartilages. 

Classification. — Only  one  kind — the  vertebral  ar- 
ticulation of  the  body. 

SPLAXCHNOLOGY. 

The  study  of  viscerae  and  the  annexes,  or  those  of 
digestion,  respiration,  urination  and  generation. 

Nomenclature. — Absolute,  as  the  liver,  spleen,  kid- 
neys ;  or  from  their  form,  the  coecum,  vagina ;  their 
situation,  the  intestines,  epididymis;  their  direction, 
the  rectum;  structure,  the  ovaries,  the  many  leaves 
or  third  stomach  of  ruminants  ;  uses — as  the  lungs, 
oesophagus. 

Number. — They  are  generally  single  in  digestive 
organs,  and  double  in  others. 

Form — Varies ;    are  generally  asy metrical. 

Situation. — In  the  splanchnic  cavities ;  sometimes 
outside  of  them. 


INTRODUCTORY.  15 

A.\GEI0L0G1. 

Study  of  vascular  system,  arteries,  veins  and  lym- 
phatics. 

Arteries. — They  form  two  systems,  the  pulmonary 
and  .aortic. 

General  form. — Dycotyledonic  division,  or  two  by 
two. 

Form  of  arteries. — Kegularly  c^dindrical  in  their 
wliole  length. 

Mode  of  origin. — Angular,  or  at  right,  acute  or 
obtuse  angle. 

Situation. — Generally  deeply  situated. 

Direction. — Straight  or  fluxuous. 

Connections. — With  veins,  nerves,  muscles,  bones, 
skin  and  cellular  tissue,  which  form  their  sheatli  of 
envelopment. 

Anastomoses. — By  convergence,  arches  or  transverse 
communications. 

Mode  of  distribution. — Terminal  and  collateral 
brandies ;  the  terminal  form  the  capillary  subdivision. 

Structure. — They  have  tlu'ee  coats,  one  internal 
serous,  one  middle  fibro-elastic,  one  external  cellular ; 
they  receive  nerves  from  the  ganglionary  or  cerebro- 
spinal axis,  also  blood-vessels  forming  the  vasa  vasorum. 
They  present  some  anomalies. 


16  EQUINE  ANATOMY. 

IVEUROLOGY. 

The  study  of  the  nervous  system. 

Division. — Composed  of  two  portions,  a  central  or 
cerebro-spinal,  and  a  peripheric,  or  the  nerves. 

Central  portion. — Consists  of  the  spinal  marrow, 
and  the  encephalon  divided  into  ithsmus,  cerebellum 
and  cerebrum. 

Nerves — Form  is  like  fasciculated  cords. 

Origin. — By  two  roots,  a  superior  and  an  inferior, 
w^hich,  in  uniting,  present  a  ganglion. 

Termination. — In  Ijranches  to  the  organs  of  animal 
life  ;  and  by  pairs.  j)erfectly  alike  or  symmetrical,  to 
the  organs  of  nutrition,  or  of  vegetable  life. 

Structure. — A  white  substance,  a  neurilemma, 
nerve  fibres  and  nerve  cells. 

Functions. — They  conduct  tlie  nervous  currents, 
possessing  a  centripetal  current  for  the  superior  root, 
and  a  centrifuo-al  for  the  inferior  one. 


CHAPTER  11. 


EXTREMITIES. 


ANTERIOR    OR    THORACIC. 

OSTEOLOGY. 

Shoulder. 

Scapula. — Division  :  Two  faces,  three  borders,  tliree 
angles.  External  face  :  Spine  of  omoplate  or  acro- 
mion, its  tuberosity,  supraspinous  and  infraspinous 
fossa,  medullary  foramen.  Internal  face  :  sub-scapular 
fossa,  two  triangular  surfaces.  Superior  border: 
cartilage  of  prolongation.  Anterior  border :  thin  and 
sharp.  Posterior  border:  thick  and  concave.  Cervical 
angle,  thin.  Dorsal  angle,  thick.  Humeral  angle, 
glenoid  cavity,  coracoid  process  with  its  tuberosity  and 
beak. 

Development :  two  nuclei  of  ossification. 

Arm. 

Humerus. — Division  :  A  body  and  two  extremities. 
Body  has  four  faces.     Anterior  face  :    smooth.     Pos- 


18  EQUINE  ANATOMY. 

terior  face :  smooth  and  round  from  side  to  side. 
External  face  :  has  the  groove  of  torsion,  external  or 
deltoid  tuberosity  with  crests  above  and  below.  In- 
ternal face :  has  an  internal  tuberosity,  medullary 
foramen.  Superior  extremity  :  has  a  head,  the  great 
and  small  trochanters,  bicipital  groove.  Inferior  ex- 
tremity :  shows  median  trochlea ;  externally,  a  trochlea  ; 
internally,  a  condyle,  epitrochlea,  epycondyle,  coronoid 
fossa,  olecranon  fossa,  on  each  side  eminences  and 
cavity  for  ligamentous  insertions. 

Development :  six  nuclei  of  ossification. 

Fore-arm. 

Kadius. — Body,  two  faces :  Anterior  face,  convex  and 
smooth.  Posterior  face  has  triangular  surface,  groove 
for  radio-cubital  arch,  eminence  of  implantation. 
Superior  extremity :  articular  surface  for  humerus, 
external  and  internal  tuberosities,  coronoid  process, 
f acettes  for  the  cubitus.  Inferior  extremity  :  articular 
surfaces  for  the  carpus,  external  and  internal  tuberos- 
ities, four  grooves,  a  rough  crest  behind. 

Development :  three  nuclei  of  ossification. 

CuBTTLTS. — Body  with  three  faces :  Anterior  face,  artic- 
ulates with  the  radius.  External  face,  convex.  Inter- 
nal face,  concave.    Three  borders  which  separate  them. 


EXTREMITIES.  19 

Superior  extremity  :  olecranon,  its  tuberosity  and  beak, 
sigmoid  notch.     Inferior  extremity  :  sharp. 
Development :  two  centres  of  ossification. 

Digital  Region. 

Carpus. — Offers  six  faces  ;  anterior  face  :  convex  ; 
posterior  face  :  very  rough  and  irregular  ;  superior  and 
inferior  faces  articular  ;  two  lateral  faces  :  rough.  It 
is  composed  of  seven  or  eight  bones  arranged  in  two 
rows.  Superior  row  has  four  bones :  the  trapezium 
with  two  facettes,  the  cuneiform  with  five,  the  lunar 
with  six,  the  scaphoid  with  four.  The  inferior  row 
has  three  bones;  the  unciform  wdth  four  facettes,  the 
magnum  with  seven,  the  trapezoid  with  five. 

Development :  each  one  centre  of  ossification. 

Metacarpi. — Three.  Principal. — Body  has  an  an- 
terior face,  smooth  and  convex ;  a  posterior  face,  with 
nutritive  foramen,  articular  surfaces  for  rudimentary 
metacarpi ;  superior  extremity,  flat  f accettes  for  the 
carpus ;  inferior  extremity,  with  two  condyles,  median 
spine,  cavities  on  each  side. 

Development:  two  nuclei  of  ossification. 

HuDiMENTARY. — Tlircc  faccs ;  a  superior  extremity  : 
articular ;  an  inferior,  w^ith  button. 

Development :  one  nucleus  of  ossification. 


20  EQUINE    ANATOMY. 

Phalanges. 

1.  Os  suFFRAcuNis. — Bodj  lias  two  faces;  anterior 
face :  slightly  rough  ;  posterior  face :  flat.  Has  two 
lateral  borders.  Superior  extremity :  two  glenoid  cav- 
ities, median  grove  ;  inferior  extremity :  two  condyles, 
median  groove. 

Development :  two  nuclei  of  ossification. 

2.  Os  CORONA. — 8ix  faces;  anterior  face:  slightly 
rough  ;  posterior  face :  elongated  f acette ;  lateral  face ; 
for  muscular  insertions ;  superior  face :  two  glenoid 
cavities,  median  eminence ;  inferior  face :  two  condyles, 
median  groove. 

Development:  one  nucleus  of  ossification. 

3.  Coffin  or  pedal  bone. — Three  faces;  anterior 
face :  preplantar  fissure,  patilobe  eminence  :  inferior 
face :  semilunar  crest,  sole,  plantar  fissure,  plantar 
foramen ;  superior  face :  glenoid  cavities,  antero- 
posterior eminence.  Three  borders ;  superior  border ; 
pyramidal  eminence,  f acettes  of  insertion ;  anterior 
border :  sharp  and  perforated ;  posterior  border : 
f  iCettes  for  navicular  bone.  Two  extremities  with 
basilar  process  above,  retrosal  below,  notch  or  foramen 
between  these. 

Development :  one  nucleus  of  ossification. 
Appendages :  Lateral  Cartilages. 


EXTREMITIES.  21 

Sesamoids. — Two  in  number,  three  faces  ;  anterior 
face  :  articular,  concave  facettes ;  external  face  :  for 
implantation;  posterior  face  :  covered  by  fibro-cartilage. 
Base  for  ligamentous  insertion  and  looking  down. 
Apex  looks  upwards. 

Development :  one  nucleus  of  ossification. 

Navicular. — Anterior  face  :  articular,  two  concave 
facettes,  median  eminence ;  posterior  face  :  covered 
with  iibro  cartilage ;  anterior  border :  flat  facette ; 
posterior  border  and  two  extremities  for  ligamentous 
attachments. 

Development :  one  nucleus  of  ossification. 

SYNDESMOLOGY. 

ScAPULo-HUMERAL  JOINT. — Eiiartlirosis.  Glenoid 
cavity  of  scapula  and  articular  head  of  humerus. 
Capsular  ligament  with  two  re-enforcing  bands.  One 
synovial  capsula.     All  motions. 

HuMERO  -  RADIAL  JOINT. — Augular  ginglymus  or 
perfect  hinge.  Condyle  and  double  trochlea  of 
humerus,  glenoid  cavity  and  double  groove  of  radius 
with  sigmoid  notch  of  cubitus.  One  anterior  capsular 
ligament  and  two  funicular  lateral,  the  internal  the 
longest,  the  external  the  thickest.  One  synovial 
capsula  with  three  culs  de  sac.  Flexion  and  exten- 
sion. 


22  EQUINE  ANATOMY. 

Radio-cubital  joint. — Diarthrodial  and  synarthro- 
dia!. For  the  first  arthrodia,  two  flat  facettes  on  each 
bone.  For  the  second,  two  rough  surfaces,  having  the 
radio-cubital  arch  between  them.  Two  interosseous  and 
two  peripheral  bands.     Yery  limited  motion  in  youth. 

Caepal  joint. — Division:  Radio-carpal, carpo-carpal, 
carpo-metacarpal,  superior  inter-carpal,  and  inferior 
inter-carpal. 

Radio-caepal  joint. — Imperfect  hinge.  On  radius, 
outward,  a  wide  groove,  small  glenoid  cavity  ;  inward, 
condyle  with  small  glenoid  cavity.  On  carpus,  superior 
face  of  upper  row.  Three  posterior  ligaments.  One 
synovial  capsula,  common  to  upper  part  of  upper 
inter-carpal  joint.     Flexion  and  extension. 

Carpo-carpal  joint. — Imperfect  hinge.  Articular 
surfaces  irregular,  those  of  the  inferior  face  of  the 
bones  of  the  upper  row,  and  those  of  the  superior  face 
of  the  bones  of  the  lower  row.  Three  ligaments,  two 
posterior  and  a  third  outside,  from  the  trapezium  to 
the  cuneiform  bone.  One  synovial  capsula,  with  culs 
de  sac  to  lower  part  of  superior  inter-carpal,  and  to 
upper  part  of  lower  inter-carpal  joint.  Flexion  and 
extension. 

Carpo-metacarpal  joint. — Arthrodia.  On  both 
bones  flat  facettes.  !Six  ligaments  :  two  anterior,  two 
posterior,   two    interosseous.      One    synovial    capsula, 


EXTREMITIES.  23 

extending  to  lower  part  of  inferior  inter-carpal  joint. 
Limited  gliding. 

Upper  inter-carpal  Joint. — Arthrodia.  Facettes 
of  lateral  faces  of  the  bones  of  the  first  row.  Six 
ligaments :  three  anterior,  and  three  interosseous. 

Lower  inter-carpal  joint. — Arthrodia.  Facettes 
of  lateral  faces  of  the  bones  of  the  second  row.  Four 
ligaments:  two  anterior,  and  two  interosseous.  For 
both  of  these  joints,  more  or  less  gliding  motion. 

Ligaments  common  to  all  joints,  four :  one  anterior 
capsular ;  one  posteiior  capsular ;  one  external  and 
one  internal  funicular.  Motions  common  to  all  the 
carpal  joints  :  flexion,  extension,  abduction,  adduction, 
and  circumduction. 

Metacarpo-phalangeal  joint. — Perfect  hinge.  On 
metacarpus,  two  condyles,  and  antero-posterior  emi- 
nence ;  on  lower  surface,  two  glenoid  cavities,  separated 
by  median  groove  on  os  suffraginis,  extended  on  the 
anterior  face  of  the  large  sesamoids.  Six  ligaments 
for  the  bones  of  tlic  lower  surface ;  three  inferior  sesa- 
moids ;  one  interosseous  sesamoid,  two  lateral.  Four 
ligaments  for  the  metacarpus,  with  the  bones  of  the 
lower  surface ;  one  anterior  capsular ;  one  posterior, 
superior  sesamoid  or  suspensory ;  two  laterals.  One 
synovial  capsula.     Flexion  and  extension. 

First   inter-phalangeal   joint. — Imperfect  hinge. 


24:  EQUINE    ANATOMY. 

On  OS  suffraginis,  two  condyles  and  antero-posterior 
groove.  On  os  coron^^  two  glenoid  cavities  separated 
bv  median  eminence,  and  extendend  backwards  by 
fibro-cartilage.  Two  lateral  ligaments  ;  one  synovial 
capsula.     Flexion,  extension  and  limited  rotation. 

Second  inter-phalangeal  joint. — Imperfect  hinge. 
On  OS  coronae,  two  condyles  and  antero-posterior 
groove  ;  on  os  pedis,  two  glenoid  cavities  with  median 
eminence,  extended  upon  the  anterior  face  of  the  nav- 
icular. Five  ligaments  :  one  interosseous,  two  anterior, 
and  two  posterior  lateral ;  one  synovial  capsula.  Flex- 
ion, extension  and  limited  rotation. 

MYOLOGY, 

Scapular  Region. — Division  :  External  and  internal. 
External  region,  four  muscles. 

1.  Long  abductor  of  the  arm. — Synonyms.  Great 
scapulo-humeral,  (G*).  Teres  major,  (P).  Great  scap- 
ulo-trochiterius,  (L).  Attachments :  Dorsal  angle  of 
the  scapula,  tuberosity  of  the  acromion,  external  tuber- 
osity of  the  humerus.  Action  :  Abductor  and  rotator 
outwards  of  the  arm. 

2.  Short  abductor  of  the  arm. — Synonyms.  Small 
scapulo-humeral,  (G).  Teres  minor,  (P).  Attach- 
ments :  Posterior  border  of  the  scapula,  infra  spinous 


*  G  is  abbreviation  of  Girard;  P,  of  Percivall;  L,  of  Ley h. 


fossa — to  the  liiimerns  between  the  crest  of  the  tro- 
chiter  and  the  deltoid  imprint.  Action  :  Abductor  and 
rotator  outwards  of  the  arm. 

3.  SupERSPiNATUs. — Sjuouyms.  Super  acromio-tro- 
chiterius,  (G).  Antea  spinatus,  (P).  Anterior  spina- 
tus,  (L).  Attachments :  Cartilage  of  prolongraent  of 
the  scapula,  internal  face  of  the  scapular  aponeurosis, 
supraspinous  fossa,  anterior  border  and  cervical  angle 
of  the  scapula,  summit  of  the  trochiter  and  trochin. 
Action :  Extensor  of  the  arm,  and  tensor  of  the  coraco- 
radialis  aponeurosis. 

4.  SuBSPiNATUs. — Synonyms.  Sub-acromio-trochi- 
terus,  (G).  Postea  spinatus,  (P).  Posterior  spinatus, 
(L).  Attachments  ;  Infraspinous  fossa,  acromion  spine 
and  tuberosity,  cartilage  of  prolongment  of  the  scapula, 
the  internal  face  of  scapula  aponeurosis,  inside  the 
convexit}'  of  the  great  trochanter  to  the  crest  of  the 
same  below.  Action :  Abductor  and  rotator  outwards 
of  the  humerus. 

Internal  region,  four  muscles. 

1.  SuBscAPULARis. — Synouyms.  Subscapulo-troch- 
ineus,  (G).  Attachments  :  Sub-scapularis  fossa,  trochin 
of  humerus.     Action  :  Adductor  of  the  arm. 

2.  Adductor  OF  THE  ARM. — Synonyms.  Subscapulo- 
humeralis,  (G).  Teres  major,  (P).  Great  scapulo- 
hunieralis,    (L).     Attachments :    Dorsal  angle  of    the 


26  EQUINE    ANATOMY. 

scapula,  posterior  border  of  the  subscapularis  muscle, 
internal  tuberosity  of  the  body  of  the  humerus.  Ac- 
tion: Adductor  and  rotator  inward  of  the  humerus. 

3.  CoEAco-HUMERALis. — Coraco-bracliialis,  omo-bra- 
chialis.  Synonyms.  Coraco-humeralis,  (P).  Middle 
scapulo-humeralis,  (L).  Attachments :  Beak  of  the 
coracoid  process,  above  internal  tuberosity  of  the 
humerus,  and  below  it  towards  the  anterior  face  of  that 
bone.     Action  :  Adductor  and  rotator  inward. 

4.  ScAPULo-HUMERAL  GRELE. — Syuouyms.  Not  de- 
scribed by  P.  Tensor  of  capsular  ligament,  (L).  At- 
tachments :  Rim  of  the  glenoid  cavity  of  the  scapula, 
and  below  the  head  of  the  humerus.  Action  :  Raises 
the  capsular  ligament  of  the  joint. 

Humeral  Region. — Division :  Anterior  and  poste- 
rior. 

Anterior  region,  two  muscles. 

1.  Long  flexor  of  the  fore- arm. — Synonyms.  Cor- 
aco-cubitalis  or  coraco-radialis,  (G).  Flexor  brachii,(P). 
Scapulo  or  coraco-radialis,  (L).  Attachments  :  Tuber- 
osity of  coracoid  process,  supero-internal  tuberosity  of 
radius  and  anterior  extensor  of  the  metacarpus  muscle 
by  a  tendinous  band.  Action:  Flexor  of  the  fore-arm, 
and  tensor  of  the  antibrachial  aponeurosis. 

2.  Short  FLEXOR  OF  the  fore- ARM. — Synonyms.  Ob- 
lique humero-cubital  or  humero-radial,  (G).     Humer- 


EXTREMITIES.  27 

alls   externus,    (P)       Humero-radialis,    (L).      Attach- 
ments :  Posterior  face  of  tlie  humerus  below  the  head, 
internal  border  of  the  radius  under  the  lateral  ligament. 
Action  :  Flexor  of  the  fore-arm. 
Posterior  region,  five  muscles. 

1.  Long  extensor  of  the  fore-arm. — Synonyms. 
Long  scapulo-olecranius,  (G).  Portion  of  the  caput  mag- 
num of  the  triceps  extensor  brachii,  (P).  Long  scap- 
ulo-olecranius, (L).  Attachments  :  Posterior  border 
of  tho  scapula,  posterior  border  of  the  olecranon  and 
the  antibrachial  aponeurosis.  Action :  Extensor  of 
the  fore-arm,  and  tensor  of  the  antibrachial  aponeu- 
rosis. 

2.  Large  extensor  of  the  fore -arm. — Synonyms. 
Great  scapulo-olecranius,  (G).  Portion  of  the  caput 
magnum  of  the  triceps  extensor  brachii,  (P).  Attach- 
ments :  Dorsal  angle  and  axillary  border  of  the  scapula, 
summit  of  the  olecranon.  Action :  Extensor  of  the 
fore-arm. 

3.  Short  extensor  of  the  fore- arm. — Synonyms. 
Humero-olecranius  externus,  (G).  Caput  medium,  (P). 
Attachments :  Curved  line  extending  from  the  deltoid 
tuberosity  to  the  head  of  the  humerus,  and  to  the  ole- 
cranon.    Action  :  Extensor  of  the  fore-arm. 

4.  Middle  extensor  of  the  fore-arm. — Synonyms. 
Humero-olecranius  internus,  (G).     Caput  parvum,  (P). 


28  EQUINE    ANATOMY. 

Attachments  :  Internal  face  of  the  humerus,  summit  of 
the  olecranon,  and  a  little  below.  Action  :  Extensor 
of  the  fore-arm. 

5.  Small  extensok  of  the  fore-aem.  Synonyms. 
Anconeus.  Small  olecrano-humeralis,  (G).  Attach- 
ments :  Margin  of  the  olecranon  fossa,  anterior  and 
external  part  of  the  olecranon.  Action :  Extensor  of 
the  fore-arm. 

Antibrachial  Region,— Division.  Anterior  and  pos- 
terior. 

Anterior  region,  four  muscles. 

1.  Anterior  extensor  of  the  metacarpus. — Syno- 
nyms. Epicondylo-premetacarpeus,  (G).  Extensor 
metacarpi  magnus,  (P).  Humero-metacarpeus,  (L). 
Attachments :  Crest  limiting  downwards  the  groove  of 
torsion  of  the  humerus,  above  and  in  front  of  the  infe- 
rior articular  surface  of  the  humerus,  supero-anterior 
tuberosity  of  the  principal  metacarpal  bone.  Action  : 
Extensor  of  the  metacarpus. 

2.  Oblique  extensor  of  the  metacarpus. — Syno- 
nyms. Cubito  or  radio-premetacarpeus,  (G).  Extensor 
metacarpii  obliquus  vel  parvus,  (P).  Kadio-metacar- 
peus,  (L).  Attachments :  External  side  of  the  radius, 
head  of  the  internal  small  metacarpal.  Action  :  Exten- 
sor and  rotator  of  the  metacarpus. 

3.  Anterior  extensor  of  the  phalanges. — Syilo- 


EXTREMITIES.  29 

nyras.  Epicondjlo-prephalangeus,  (G).  Extensor  pedis, 
(P).  Humero-prephalangens,  (L).  Attachments  :  Be- 
low the  crest  limiting  the  groove  of  torsion  of  the 
humerus  behind,  in  front  of  the  inferior  tuberosity  of 
that  bone,  external  ligament  of  the  elbow  joint,  supero- 
external  tuberosity  of  the  radius,  external  border  of 
the  same  bone,  pyramidal  eminence  of  the  os  pedis. 
Action  :  Extends  the  third  phalanx  upon  the  second, 
this  upon  the  first,  and  that  upon  the  metacarpal. 

4.  Lateral  extensor  of  the  phalanges. — Syno- 
nyms. Cubito  or  radio-prephalangeus,  (G).  Extensor 
suffraginis,  (P).  Attachments  :  External  tuberosity  of 
the  radius,  external  lateral  ligament  of  the  elbow  joint, 
on  the  body  of  botli  bones  of  the  fore-arm,  capsular 
ligament  of  the  fetlock  joint,  and  superior  extremity  of 
the  OS  suffraginis.  Action :  Extensor  of  the  digital 
region  proper. 

Posterior  region,  five  muscles. 

1.  External  flexor  of  the  metacarpus. — Syno- 
nyms. Epicondylo-supercarpeus,  (G).  Flexor  metacarpi 
extern  us  5  (P).  Humero-supercarpeus  externus,  (L). 
Attachments :  Summit  of  epitrochlea,  the  trapezium 
and  the  head  of  the  external  small  metacarpal.  Action  : 
Flexor  of  the  metacapus. 

2.  Oblique  flexor  of  the  metacarpus. — Synonyms. 
Epitrochlea  supercarpeus,  (G).     Flexor  metacarpi  med- 


30 


EQUINE    ANATOMY. 


ins,  (P).  Humero-metacarpeus  interims,  (L).  Attach- 
ments: Base  of  the  epicondyle,  olecranon  and  the  trape- 
siiim.     Action  :  Flexor  of  the  metacarpus. 

3.  Internal  flexor  of  the  metacarpus. — Synonyms. 
Epitrochlea  metacarpeus,  (G).  Flexor  metacarpi  inter- 
nus,  (F).  Humero  metacarpeus  internus,  (L).  Attach- 
ments :  Base  of  the  epicondyle,  the  head  of  the  inter- 
nal metacarpal.     Action  :  Flexor  of  the  metacarpus. 

4.  Superficial  flexor  of  the  phalanges. — Syno- 
nyms. Epitrochlo-phalangeus,  (G).  Flexor  pedis  per- 
foratns,  (F).  Humero  coronaris  or  phalangeus,  (L). 
Attacliments  :  Summit  of  the  epicondyle,  the  extremi- 
ties of  the  pulley  behind  the  superior  extremity  of  the 
OS  coronge.  Action  :  Flexes  the  second  phalanx  on  the 
first,  this  on  the  metacarpal,  and  the  whole  digital 
region  on  the  fore-arm. 

5.  Deep  flexor  of  the  phalanges. — Synonyms. 
Cubito  or  radio-phalangeus,  (G).  Flexor  pedis  perfor- 
atus,  (P).  Humero-radio-phalangeus,  (L).  Attach- 
ments :  Summit  of  the  epicondyle,  summit  and  pos- 
terior border  of  the  olecranon,  posterior  face  of  the 
radius,  plantar  crest  of  the  os  pedis.  Action  :  Flexes 
the  phalanges  on  each  other  and  on  the  metacarpus, 
and  the  wliole  foot  on  the  fore-arm. 


EXTREMITIES.  31 

ANGEiOLOGY. 

Arteries  :  the  superior  and  inferior  scapular  with 
the  humeral. 

Superior  scapular,  or  superscapular — collateral 
branch  of  the  axillary  artery — I'uns  upwards  between 
the  subscapularis  muscle  and  the  antea-spinatus,  and 
terminates  at  the  lower  part  of  the  scapula. 

Inferior  scapular,  or  subscapular ^  also  collateral 
branch  of  the  axillary,  runs  between  the  subscapularis 
muscle  and  the  adductor  of  the  arm  to  the  dorsal 
angle  of  the  scapula;  it  li'is  collateral  branches  to  tlie 
latissimus  dorsi  muscle,  one  forming  the  posterior  cir- 
cumflex of  the  shoulder,  and  also  anterior  and  posterior 
muscular  branches. 

Humeral  artery  is  tlie  terminal  branch  of  the  axil- 
lary. It  runs  down  inside  of  tlie  arm  to  the  inferior 
extremity  of  the  humerus,  where  it  terminates  by  the 
anterior  and  posterior  radial.  Its  collateral  branches 
are :  1 — the  prehumeral  or  anterior  circumflex  of  tlie 
shoulder  going  to  the  mastoido-humeralis  muscle  ;  2 — 
the  external  collateral  of  the  elbow,  or  deep  humeral, 
passing  to  the  large  extensor  of  the  fore-arm,  and  by 
another  branch  to  the  front  of  the  elbow  joint ;  3 — the 
internal  collateral  of  the  elbow,  epicondyloid  or  cubital 
artery,  terminating   at   the   carpus  anastomosing  with 


32  EQUINE    ANATOMY. 

the  posterior  radial  artery ;  4 — the  principal  artery  of 
the  coraco  radialis,  dipping  into  that  muscle  by  ascend- 
ing and  descending  branches. 

Anterior  radial  artery  passes  in  front  of  the 
elbow  joint,  under  the  flexor  muscles  of  the  fore-arm 
and  of  the  anterior  extensor  metacarpi,  to  the  anterior 
face  of  the  radius,  to  the  knee,  where  it  looses  itself  by 
anastomosing  with  tlie  posterior  radial  and  the  inter- 
osseous of  the  fore-arm. 

Posterior  radial  artery  runs  down  under  the  in- 
ternal ligament  of  the  elbow  joint,  under  the  internal 
flexor  of  the  metacarpus,  arrives  at  the  inferior  extrem- 
ity of  the  radius,  and  terminates  by  the  common  trunk 
of  the  interosseous  metacarpal  and  the  collateral  of 
the  cannon.  Its  collateral  brandies  are  :  1 — articular 
branches  ;  2 — muscular  braiK^hes  to  tlie  posterior  anti- 
brachial   muscles ;    3 — interosseous    of    the   fore-arm, 

which  runs  through  the  radio  cubital  arch  under  the 

I* 
extensor  suffraginis  ;  4 — small  muscular  and  musculo- 
cutaneous branches  ;  5 — branches  to  the  posterior  face 
of  the  radius. 

Common  trunk  of  the  interosseous  metacarpal. — 
Passing  inwards  and  behind  the  carpus,  it  reaches  the 
head  of  the  internal  small  metacarpus,  bends  outwards 
under  the  superior  extremity  of  the  suspensory  liga- 
ment, and  anastomoses  witli  a  branch  from  the  super- 


EXTREMITIES.  *  33 

iicial  arch  which  unites  tlie  cubital  artery  with  the 
collateral  of  tlie  cannon,  forming  then  the  sub-carpal 
arch — tlie  super-carpal  arcli  being  formed  by  the  anas- 
tomosis of  the  collateral  of  the  cannoji  and  the  epicoiir/ 
dyloid  itself.  Collateral  branches :  two  posterior 
interosseous-metacarpal  or  palmar,  and  two  anterior  or 
dorsal.  The  posterior  run  on  the  inside  of  both  small 
metacarpal  bones,  anastomosing  downwards  with  the 
collateral  of  the  cannon.  The  anterior  runs  on  the 
outside  of  both  small  metacarpal  bones,  and  downwards 
anastomoses  also  with  branches  of  the  collateral  of  the 
cannon. 

Collateral  artery  of  the  cannon. — Passes  under 
the  carpal  arch  downward  on  the  internal  side  of  the 
flexor  tendons  to  the  fetlock,  and  ends  in  the  digital 
artery.  Collateral  branches  are  :  1 — to  the  epicondy- 
loid  artery  to  form  the  supracarpal  arch;  2 — synovial, 
tendinous^  and  cutaneous  ramuscules :  3 — branch  to 
the  posterior  interosseous  of  the  metacarpal. 

Digital  artery.— On  each  side  of  the  fetlock  joint 
it  runs  down  to  the  basilar  process  and  terminates  in  the 
ungueal  plantar  and  preplantar  arteries.  Collateral 
branches  :  1 — articular  to  the  fetlock  ;  2 — branch  to 
the  tissue  of  the  ergot;  3 — the  perpendicular  artery 
of  Percivall,  ramifying  into  anterior  and  posterior 
branches ;  4 — the  artery  of  the   plantar   cushion  run-  yj-- 


-C^i^MjjC  y2^.««.-<.--C£o^ 


34  EQUINE    ANA'HJMY. 

iiiug  downwards  to  that  apparatus  ;  5 — tendinous  and 
cutaneous  branches  to  the  lirst  and  second  phalanges ; 
6 — the  coronary  circle  or  two  branches,  anterior  and 
posterior,  running  round  the  coronet  and  anastomos- 
ing with  those  of  tlie  opposite  side. 

Ungueal  preplaktar. — Passes  through  the  notch  of 
the  lateral  extremity  of  the  os  pedis,  goes  to  the 
preplantar  fissure,  runs  forwards,  and  ends  by  divisions 
dipping  into  the  os  pedis.  /  ^  ^<n4^v.vw^  u^  U""^ 

Ungueal  plantar. — Lodged  in  the  plantar  fissure, 
then  in  the  plantar  canal,  and  into  the  semi-lunar 
sinus  of  the  os  pedis,  it  anastomoses  wtt^h  that  of  the 
opposite  side,  forming  tlie  semi-lunar  arch.  Collateral 
branches  ascend  to  form  the  anterior  laminal  of 
Spooner,  and  descend  to  form  the  inferior  commu- 
nicating arteries. 

Veins. — Digital  veins,  wliicli  form  in  tb.e  foot  a  rich 
network — satellite  of  the  arteries  of  that  region — 
emptying  into  three  metacarpal  or  collateral  of  the  can- 
non ;  these  are  two 'superficial  veins  on  each  side  of 
the  flexor  tendons,  and  a  third,  deep,  passing  under 
the  suspensory  ligament.  Following  these  are  two 
groups  of  autibrachial  veins,  one  formed  by  tlie  cubital 
and  the  posterior  radial,  which  run  alongside  the  arter- 
ies of  the  same  name;  the  other,  the  median  vein, 
which  receives  the  superficial  anterior  radial.     These 


EXTREMITIES.  35 

antibracliial  unite  with  the  anterior  radial,  satellite  of 
the  artery  of  the  same  name,  and  form  the  humeral 
vein,  which  receives  the  subcutaneous  thoracic  and  the 
subscapular,  to  form  the  axillary  which  empties  into 
the  confluent  of  the  jugular. 

LymphaticSi — Coming  from  all  parts  of  the  limb, 
they  pass  to  the  prescapular  and  brachial  glands,  which 
send  out  numerous  efferent  branches,  terminating  in 
the  prepectoral  glands. 

NEUROLOGY. 

Brachial  plexus. — Formed  by  the  sixth,  seventh 
and  eighth  cervical,  and  two  flrst  dorsal  p  ^irs  of  rach- 
idian  nerves,  it  lies  outside  of  the  two  portions  of  the 
scalenus  muscle,  under  the  shoulder  near  the  scapulo- 
humeral angle,  and  divides  iiito  fourt^yp  ^if'Blp^^^y^ 
"7r~l.  DiaphrIgmatic  NERViPruns  inside  the  thoracic 
cavity,  along  the  course  of  the  axillary  artery  with 
the  pncumogastric,  there  it  receives  branches  from 
the  sympathetic  nerve,  reaches  the  base  of  tlio  heart, 
runs  under  tlie  pleura  to  the  phrenic  mrt  of  the  dia- 
phragm, wliere  it  ends.^"^  K^xJi^t^  -^ka-*«^^ 

2.  Nerve  of  the  angularis  and  rhomhoideus  mus- 
cles, formed  by  the  sixth  cervical  pair,  runs  upward 
to  these  two  muscles. 

3.  Nerve    oFyTUK    serratus    magnus    or  ^super^r 

y  ^  ^  «■  ^^^^  ^,*«*, -H-r^   • ' 


^    ^^^.KO^ 


36  EQUINE    ANATOMY. 

thoracic,  from  the  sixtli  and  seventh  cervical  pairs,  runs 
across  the  serratiis  niagniisiiniscle  aiKJ  terminates  in  it. 

4.  ^ERVE  OF  THE  PECTORAL  MUSCLES  or  inferior 
thoracic:  five  principal;  one  to  the  sterno  prescapulafis 
muscle,  another  passing  between  the  two  pectoral  mus- 
cles and  ramifying  in  the  superficial  pectoral,  the  three 
other  branches  going  to  tlie   sterno  trochineus  muscle. 

5.  Subcutaneous  thoracic  neryj:  rises  in  common 
with  the  cubital  nerve  and  runs  backward  on  the  in- 
ternal face  of  the  long  extensor  of  the  fore  arm  and 
of  the  panniculus  carnosus,  as  far  as  the  flank,  where 
it  terminates  in  the  subcutaneous  muscle  of  that 
region. 

6.  ISeRVE  of  THE    LATISSIMUS    DORSI    fomicd     bv     tllC 

eighth  cervical  pair,  runs  upwaids   and  backwards  to 
that  muscle,  where  it  is  distributed. 

7.  Axillary  or  circumflex  nerve,  from  the  eight 
€crvical  pair,  runs  backwards  and  downwards  on  the 
internal  face  of  the  subscapularis  muscle,  passes  be- 
tween it  and  the  teres  major,  crossing  tlie  subscapular 
artery ;  behind  the  scapulo-humeral  joint,  passes  be- 
tween the  short  abductor  of  the  arm,  the  great  and 
middle  extensor  of  tlie  fore  arm,  reaches  the  long  al)- 
ductor  of  the  arm  and  terminates  in  tlie  two  abductors, 
the  mastoido  humeralis  and  tlie  skin. 

8.  Nerve  of  the  adductor  of  the  arm,  also  from 


EXTREMITIES.  37 

the    eighth    cervical     pair    to     tlie     ad(hictor    muscle. 
9.  Nerve    of    the    subscapularis     Muscr.E. — Two 
braiicly3s  ramifying  in  that  muscle,     y^ ^-"^^^^^^^^^ 

0/Sus-scAPULAR  nerve. — Formed  ])y  the  sixth 
and  "seventh  cervical  pairs,  running  backwards  between 
tlie  angnlaris  scapulae,  tlie  sterno  prescapularis  and 
the  antea  spinatus  muscles,  reaches  the  posterior  fossa 
of  the  external  face  of  the  scapula,  where  it  termi- 
nates in  the  postea  spinatus  muscle. 

11.  Anterior  brachial  nerve  or  musculo-cutane- 
ous. — Formed  hy  the  seventh  and  eighth  cervical  pairs 
— situated  on  the  inside  of  the  scapulo  humeral  joint, 
crossing  the  axillary  artery  and  passing  underneath  it, 
united  to  the  median  nerve,  runnino-  in  frpnt  of  it  to 
the  bifurcation  of  the  omo-brachialis  muscle,  passing 
between  its  branches  and  (iippin^  into,-;  the  coraco- 
radialis  mnscle.    =    'f^^^    ^x^^.^^'H^ 

12.  Radial  nerve. — Tlie  largest  of  the  plexus — 
formed  principally  by  the  iirst  dorsal  pair.  It  passes 
downwards  and  backwards,  under  and  across  the  sub- 
scapularis and  adductor  nmscles  parallel  to  the  hume- 
ral artery  and  posterior  to  the  cubital  nerve.  At  the 
deep  humeral  artery  it  passes  behind  the  humerus,  un- 
der and  then  alongside  the  short  flexor  of  the  fore- 
arm to  the  anterior  face  of  the  elbow  joint  and  the 
radius ;  then   under  the  extensors  of  the   metacarpus 


38 


EQUINE    ANATOMY. 


and  extensor  of  the  phalanges,  meets  the  radial  art- 
ery, with  which  it  goes  to  the  oblique  extensor  of  the 
metacarpus  and  terminates.  Collateral  branches  are 
to  the  tendons  of  the  great  dorsal  and  adductor  of  the 
arm,  to  all  tlie  extensors  of  the  fore-arm,  the  skin, 
the  anterior  extensor  and  external  flexor  of  the  meta- 
carpus and  to  the  extensors  of  the  phalanges. 

13.  CuBiTO-cuTANEous  or  cubital  nerve — Formed  by 
tlie  dorsal  pairs.  It  rims  backwards  and  downwards, 
behind  the  humeral  arteiy ;  crossing  the  deep  hftmeral 
artery,  it  passes  between  the  long  and  middle  extensors 
of  ths  fore  arm,  to  the  inside  of  the  elbow,  over  the 
epitrochlea,  under  the  cubital  fasciculus  of  the  middle 
flexor  of  the  metacarpus,  under  this  muscle  to  the 
trapezium  bone,  where  it  ends  by  two  branches :  one, 
cutaneous,  passing  between  the  tendons  of  the  exter- 
nal and  middle  flexors  of  the  metacarpus  and  through 
the  antibrachial  aponeurosis  to  ramify  in  the  skin  of 
tliis  region ;  the  other,  with  a  branch  of  the  median 
nerve,  forms  the  external  plantar  nerve.  Collateral 
branches,  two :  one  to  the  skin  of  the  fore-arm  below 
the  elbow  on  the  inside,  the  other  to  some  muscles  of 
the  posterior  antibracliial  region. 

14.  CUBITO-PLANTAR  OR  MEDIAN  NERVE. Fomicd    by 

the  eiglith  cervical  and  the  dorsal  pairs.  Starts  from 
the  posterior  part   of  the  plexus  to  reacli  the  axillary 


EXTREMITIES.  39 

artery,  there  anastomoses  with  tlie  anterior  brachial 
nerve,  phices  itself  in  front  of  tlie  1  mineral  artery,  run- 
ning with  it  to  its  terminal  bifurcation,  passes  down- 
wards on  the  inside  of  the  leg  with  the  posterior  ra- 
dial artery,  arrives  at  the  elbow  joint,  becomes  poste- 
rior, and  a])ove  the  inferior  third  of  the  fore-arm  bifur- 
cates to  form  the  plantar  nerve.  Collateral  branches : 
1.  One  branch  to  the  thoracic  nerve  going  to  the  super- 
ficial pectoral  muscles.  2.  In  the  middle  of  the 
humerus,  one  branch  wdiich  passes  beneath  the  coraco- 
brachialis  and  terminates  in  two  small  branches.  3. 
In  the  antibrachial  region,  branches  to  the  internal 
flexor  of  the  metacarpal  and  to  the  flexors  of  the  pha- 
langes. 

Plantar  nerve. — External  and  internal.  Internal 
lies  beside  the  collateral  artery  of  the  cannon,  alons^- 
side  the  perforans  tendon  to  near  the  fetlock,  where 
it  terminates  by  several  digital  branches.  Collat- 
eral branches  to  the  skin  of  the  metacarpal  region, 
and  one  which  crosses  obliquely  behind  the  flexor  ten- 
dons and  unites  with  the  external  plantar  nerve.  Ex- 
ternal plantar  nerve  is  formed  by  a  branch  from  the 
cubital  and  one  from  tlie  median  nerve,  runs  in  com 
pany  with  the  external  collateral  vein  of  the  cannon 
and  an  arteriole,  outside  of  the  flexor  tendons  at  the 
superior  extremity  of  the  cannon,  inside  of  the   head 


40  EQUINE  ANATOMY. 

of  tlie  external  small  metacarpal  bone,  gives  off  the 
deep  palmar  branch,  then  passes  along  the  tendon  of 
the  perforans  muscle,  recQives  the  branch  ,  of.  the  in- 
ternal  plantar  and  at  the  fetlock  terminates  m  the 
digital  branches. 

Digital  branches,  or  collaterals  of  the  digit — three 
in  number — one  anterior,  one  middle  and  a  posterior. 
The  anterior  placed  in  front  of  the  vein  goes  to  the 
skin  of  the  anterior  face  of  the  digit.  The  middle, 
between  the  artery  and  vein,  goes  to  the  coronary 
cushion  and  the  podophyllous  tissue.  The  posterior, 
behind  the  artery  and  larger  than  the  other,  lies  first 
above  the  artery  and  then  behind  it,  runs  down  to  the 
basilar  process,  into  the  lateral  fissure  of  the  os  pedis 
and  ramifies  in  the  podophyllous  tissue  and  the  bone. 
Collateral  branches  :  1 — to  the  flexor  tendons  ;  2 — to 
the  plantar  cushion  ;  o — to  the  cartilages  of  the  os 
pedis;  4- — to  the  reticulum  of  the  podophyllous  tissue; 
5 — a  plantar  branch. 

COMPLEMENTAKY  APPENDAGES  AND  TeGUMENTARY  COV- 
ERINGS OF  THE  DIGITAL  REGION. — They  coiisist  of  the 
fibro  cartilages  of  the  os  pedis,  the  plantar  cusliion, 
and  of  the  keratogenous  membrane — the  whole  cov- 
ered by  the  horn)^  apparatus  or  hoof. 

Fibro-Cartilages  of  the  os  pedis — situated  one  on 
eacli  side — offer  an   external  fnce   convex,  an  internal 


i 


EXTREMITIES.  41 

face  concave,  continue  downwards  and  backwards  to 
the  plantar  cushion  ;  tlie  superior  border  is  thin  and 
flexible,  the  inferior  thick  and  attached  to  the  basilar 
and  retrossal  processes;  the  posterior  border  is  slightly 
convex,  the  anterior  is  intimately  united  to  the  anterior 
lateral  ligament  of  the  articulation  of  the  foot. 
Structure :  is  a  mixture  of  fibrous  and  cartilaginous 
tissue,  liable  to  calcification. 

Plantar  Cushion. — Is  a  wedge  placed  between  the 
cartilages  of  the  os  pedis,  between  the  perforans  ten- 
don and  the  inferior  wall  of  the  horny  box.  It  has 
an  antero-superior  face  covered  by  a  cell ulo- fibrous 
membrane,  and  is  moulded  on  the  aponeurotic  termina- 
tion of  the  perforans  tendon ;  its  inf ero-posterior  face 
is  covered  by  the  keratogenous  membrane  and  offers 
in  its  middle  the  pyramidal  body  representing  the 
shape  of  the  frog  of  tlie  foot.  The  base  looks  back- 
wards and  upwards ;  it  shows  on  each  side  the  bulbs  of 
the  plantar  cushion,  and  is  also  covered  by  a  cellulo- 
fibrous  covering.  The  apex  is  fixed  on  the  plantar 
face  of  the  os  pedis,  in  front  of  the  semilunai-  crest 
and  the  insertion  of  the  perforans  tendon.  The  la- 
teral borders  are  continuous  with  the  internal  face  of 
tlie  lateral  cartilages.  Its  structure  consists  of  a 
fibrous  network  mixed  with  elastic  fibres,  connective 
fibres  with  adipose  cells,  blood  vessels  and  nerves. 


42  EQUINE    ANATOMY. 

Keratogenous  membrane,  resting  upon  a  fibrous 
fascia  and  covered  by  the  lioof.  It  is  composed  of  the 
coronary  cushion,  the  velvety  and  laminal  tissues. 

Coronary  tissue,  bourrelet  or  cutidura. — It  is 
lodged  in  a  cavity  at  the  upper  border  of  tlie  horny 
case.  Its  inferior  border  is  separated  from  the 
laminae  bj  a  white  zone  ;  the  superior  border  is  limited 
by  the  perioplic  ring;  its  extremities  are  reilexed  near 
the  bulbs  of  the  plantar  cushion  into  tlie  lateral  lacu- 
nae of  the  pyramidal  body ;  its  surface  is  covered 
with  papillae,  villi  and  villous  loops  ;  its  structure  is 
the  same  as  the  cutaneous  derma,  is  very  vascular 
and  has  many  nerves ;  it  is  red,  and  sometimes  macu- 
lated black  by  pigment. 

Yelvety  tissue  covers  tlie  plantar  snrface  of  the 
OS  pedis  and  the  plantar  cusliion.  Its  surface  is  like 
those  upon  whicli  it  rests,  having  a  central  and  a  periph- 
eric portion  covered  by  the  sole.  It  is  provided  with 
numerous  villosities,  received  in  the  porosities  of  the 
sole  and  frog,  and  has  the  same  structure  as  the  cuti- 
dura, 

Laminal  or  podophyllous  tissue. — This  covers  the 
anterior  face  of  the  os  pedis.  It  consists  of  five  or  six 
hundred  laminai,  parallel,  wider  below  than  above,  den- 
ticulated on  their  free  border,  and  having  folds  on 
their  lateral  surfaces ;  they  are  received  between  the 


EXTREMITIES .  43 

laminpe  of  the  kerapliyllous  tisue.  Its  structure  is  like 
that  of  other  parts  of  the  keratogenous  apparatus. 

Hoof — is  composed  of  tliree  parts :  wall,  sole  and 
frog. 

Wall,  or  crust. — Covers  the  anterior  face  of  the 
foot,  diminishing  in  width  and  thickness  posteriorly. 
It  passes  round  the  bulbs  of  the  plantar  cushion,  is  in- 
flected inwards  and  becomes  confounded  with  the  lat- 
eral borders  of  the  sole.  It  is  divided  into  toe,  outside 
and  inside  toe,  quarter,  heels  and  bars.  Its  external 
face  is  smooth  and  covered  above  by  the  periople, 
which  is  a  dependance  of  the  frog.  The  internal  face 
presents  tlie  laminae  of  the  kerapliyllous  tissue.  Its 
superior  border  offers  the  cutigeral  cavity  with  many 
little  holes  for  the  villosities  of  the  cutidura ;  the  in- 
ferior is  united  to  the  sole,  and  the  extremities  form 
the  bars. 

Sole — is  a  horny  plate  occupying  the  inferior  face 
of  the  hoof.  The  inferior  face  is  more  or  less  concave  ; 
the  superior  has  numerous  pores  for  the  villi  of  the 
velvety  tissue  ;  the  external  border  is  united  to  the 
wall :  the  internal  forms  a  V  shaped  notch  opening 
backwards  to  receive  tlie  frog. 

Frog — is  a  pyramidal  mass  of  horn  lodged  between 
the  bars.  Its  inferior  face  has  a  median  lacuna  separ- 
ating the  branches  ;  the  lateral  faces  are  united  to  the 


44  EQUINE    ANATOMY. 

bars  and  internal  border  of  the  sole ;  on  each  side 
are  found  the  lateral  lacunae  or  commissures  of  the 
frog  ;  the  superior  face  rests  on  tlie  pyramidal  body  of 
the  plantar  cushion,  has  a  triangular  excavation  divided 
by  the  frog  stay  or  sjmie  of  the  frog ;  its  base  forms 
the  glomes  of  the  frog  ;  the  apex  rests  on  the  point  of 
the  angle  formed  by  the  posterior  border  of  the  sole. 


CHAPTER   III. 


POSTEEIOR  OR  ABDOMINAL  EXTREMITIES. 


OSTEOLOGY, 

Hip. — OssA  iNNOMiNATUM  OR  COXA,  formed  of  three 
pieces,  iliiiin,  pubis  and  ischium. 

Ilium. — Division:  Two  faces,  three  borders,  thiee 
angles.  The  external  face  presents  tlie  iliac  fossa ; 
the  internal  face  the  iliac  surface  and  an  auricular  facet 
for  articulation  with  the  sacrum.  The  anterior  border 
is  concave  ;  tlie  external  has  a  medullary  foramen  and 
vascular  grooves ;  tlie  internal  forms  the  great  sciatic 
notch.  The  anterior  external  angle  has  four  tuberos- 
ities, the  anterior  internal  only  one ;  the  posterior 
angle  offers  a  facette  for  the  cotyloid  cavity,  the  supra- 
cotyh)id  crest,  the  ileo  pectineal  eminence,  and  some 
muscular  imprints.  Development :  two  nuclei  of  ossi- 
iication. 

Pubis. — Division  :  Two  faces,  three  borders,  three 
angles.  The  superior  face  is  smooth  and  concave ; 
the  inferior  has  a  large  groove  for  the  pubio- femoral 


46  EQUINE    ANATOMY. 

ligament.  The  anterior  border  is  thin  and  rough; 
the  posterior  thick  and  concave,  and  co-operates  to 
form  the  obturator  foramen  ;  the  internal  is  thick  and 
articular.  The  external  or  cotyloid  angle  forms  the 
bottom  of  the  cotyloid  cavity  ;  the  internal  and  poste- 
rior angles  are  articular.  Development :  one  nucleus 
of  ossification. 

Ischium. — Division  :  Two  faces,  four  borders,  four 
angles.  The  superior  face  is  smooth  and  forms  the 
floor  of  the  pelvic  cavity ;  the  inferior  is  roughened  for 
muscular  attachments,  and  presents  the  ischial  crest. 
The  anterior  border  forms  the  obturator  foramen,  the 
external  the  small  sciatic  notch,  the  posterior  forms 
the  ischial  arch,  while  the  internal  is  articular.  The 
anterior  external  angle,  or  cotyloid  presents  a  diarthro- 
dial  facet  and  the  posterior  extremity  of  the  supra- 
cotyloid  crest ;  the  anterior  internal  angle  is  articulated 
with  the  pubis  ;  the  posterior  external  forms  the  ischial 
tuberosity  and  the  posterior  internal  articulates  with 
that  of  the  opposite  side.  Development :  two  nuclei 
of  ossification. 

Thi^h. — Fp:muk. — Division:  Bodv,  and  two  Extrem- 
ities. Body  lias  four  faces.  The  ant^ouTYis  smooth;  the 
posterior  has  a  rounded,  roughenec^surface,  a  slight 
crest  oblique  above,  in  the  middle  a  wide  rough  surface 
for  muscular  attixhments,  and  below  a  wide  vascular 


(r< 


(t 


V^ 


groove;  tlie  external  face  shows  tlie  siibtrocliiinterian 
crest  and  belo^y<-^:he  suscondjloid  fossa ;  the  internal 
face  shows  the  small  troclianter,  the  medullary  fora- 
men surrounded  by  muscular  imprints,  the  origin  of 
the  vascular  groove  of  the  posterior  face  and  the  sus- 
condyloid  crest.  Extremities :  The  superior  lias  an 
articular  head  and  neck,  a  great  trochanter  with  apex, 
convexity,  and  crest,  and  posteriorly  the  trochante- 
rian  fossa;  the  inferior  has  a  wide  trochlea,  with  inter- 
nal border  the  highest,  two  condyles  separated  by 
intercond^doid  notch,  two  foss?e  on  the  outside  of  ex- 
ternal condyle,  a  rough , impression  on  the  .inside  of 
the  internal  condyle,  and  a  large  tubercle  outwards; 
between  the  external  condyle  and  trochlea  a  digital  im- 
pression for  muscular  attachments.  Development  : 
four  nuclei  of  ossification. 

Le^.— Tibia. — Division  :  Body  and  two  extremities. 
Body  has  three  faces  and  three  borders.  The  external 
face  is  smooth  and  concave ;  the  hiternal  slightly  con- 
vex and  with  muscular  imprints  above ;  the  posterior 
offers  two  trian2;ular  surfaces  with  rouirh  muscular 
lines,  and  on  their  limits  the  medullary  foramen.  The 
anterior  border  forms  the  tibial  crest;  the  external,  the 
til)ial  arch ;  the  internal  is  thick  and  rounded.  Ex- 
tremities:  the  superior  has  three  tuberosities;  the  ante- 
rior or  the  tibial  tuberosity  has  a  depressed  centre  ;  the 


48  EQUINE    ANATOMY. 

external  is  articular  and  has  a  facet  on  the  outside  for 
articulation  with  the  fibula — it  is  separated  from  the 
anterior  by  a  groove  ;  the  internal  tuberosity  is  also 
articular  and  has  posteriorly  a  small  tubercle  for  liga- 
mentous attachment.  On  the  middle  of  the  superior 
extremity  is  the  tibial  spine.  The  inferior  extremity 
lias  a  double  articular  pulley,  outwards  a  tuberosity 
with  a  vertical  groove,  and  inwards  another  tuberosity 
wdth  an  oblique  groove  posteriorly.  Development : 
four  nuclei  of  ossification. 

Fibula. — Division:  Middle  part  and  two  extremities. 
Middle  part  forms  the  tibial  arch.  Extremities  :  the 
superior,  or  head,  is  wide  and  has  inwards  a  facet  for 
articulation,  outwards  it  shows  muscular  imprints  ;  the 
inferior  ends  in  a  blunt  point.  Development :  one 
nucleus  of  ossification. 

Patella. — Division  :  Three  faces  and  a  circumfer- 
ence. The  anterior  face  is  convex  and  irregular ;  the 
superior  roughened  for  muscular  attachments ;  the 
posterior  is  moulded  on  the"  femoral  trochlea.  The 
circumference  unites  with  the  three  faces.  Develop- 
ment :  one  nucleus  of  ossification. 

Digital  Region.— Tarsus. — Division:  Six  or  seven 
bones  arranged  in  two  rows.  The  superior  row  has 
the  astragalus  with  its  six  faces ;  the  superior,  anterior, 
inferior  and  posterior  are  articular ;  the   external  and 


EXTREMITIES.  49 

internal  fiirnislied  with  ligamentous  imprints.  The  os 
calcis  has  an  external  face  flat  and  smooth,  an  internal 
face  forming  the  tarsal  arc.h,  an  anterior  horder  con- 
cave, a  posterior  l)order  thick  and  rough,  a  superior 
extremity  divided  in  three  parts  :  one  middle,  for  mus- 
cular attachment ;  one  anterior,  smooth,  and  one  pos- 
terior for  the  sliding  of  a  tendon  ;  an  inferior  ex- 
tremity, articular — it  is  developed  by  t\vo  nuclei  of  os- 
sification and  the  astragalus  by  onfe"<tTi^y.  The  inferior 
row  has  four  bones  ;,\the  cul^oid  with  six  faces  ;  the 
scaphoid,  flat  bone,  with  two  faces  and  a  circumfer- 
ence ;  the  great  cuneiform  with  two  articular  faces  and 
three  borders ;  the  small  cuneiform  sometimes  divi- 
ded in  two  pieces,  with  four  facet tes  for  articula- 
lation.  Development :  all  the  bones  of  the  inferior 
row  are  dev^eloped  by  one  nucleus  of  ossification . 

Metatarsi. — Similar  to  the  metacarpi. 

Principal  Metatarsus  is  longer,  more  cylindrical 
than  the  metacarpus,  and  has  on  the  outside  border  an 
oblique  Assure.  Its  superior  articular  surface  is  hol- 
lowed by  a  fossa  of  insertion. 

Rudimentary  Metatarsi. — The  external  is  always 
the  longest  and  the  tliickest ;  the  internal  has  three 
articular  facets  on  the  superior  extremity. 

Phalanges. — Almost  exactly  like  those  of  the  an- 
terior extremity. 


50  EQUINE  ANATOMY. 

^  SYi\DESWOLOGl. 

Coxo-FEMORAL  JOINT — Eiiartlirosis.  On  the  ossa  iii- 
noniinatum  the  cotjloid  cavity,  on  the  femnr  the  artic- 
nhir  head,  both  united  by  the  capsular,  pubio  and 
coxo-femoral  ligaments.  One  synovial  capsula.  All 
motions. 

Femoro-tibial  joint — Imperfect  hinge.  On  the 
femur,  the  articular  surface  of  the  trochlea  and  tlie 
two  condyles ;  on  the  tibia  the  two  large  f acettes  at 
the  base  of  the  tibial  spine ;  on  the  patella,  its  poste- 
rior face  enlarged  by  fibro-cartilaginous  pad.  Two  in- 
ter-articular menisci :  the  internal  attached  in  front 
and  behind  tlie  tibial  spine,  the  external  fixed  forward 
near  the  internal  meniscus,  and  behind  by  two  branches, 
one  on  the  femur,  the  other  on  the  tibia.  Tliis  joint 
has  three  anterior  patellar  ligaments,  two  lateral, 
two  interosseous,  one  anterior  capsular,  with  lateral 
re-enforcing  bands,  and  one  posterior  capsular  liga- 
ment ;  three  synovial  capsulse.  Motions  :  flexion,  ex- 
tension and  rotation. 

TiBio-FiBULAR  JOINT — Artlu'odia.  Irregular  diar- 
throdial  facette  on  both  bones.  Interosseous  and 
peripheric  ligamentous  fibres,  two  small  ligamentous 
fasciculi  and  an  aponeurotic  membrane  ;  bolow  a  liga- 
mentous cord.    Motions  very  limited. 


EXTREMITIES.  51 

7 

Tarsal  joint. — Division  : ,  -Tibio-tarsal,  superior 
iiiter-tarsal,  tarso-tarsal,  inferior  inter-tarsal,  tarso-met- 
atar^a\    ^^'^^    ^xi^'^^^     '^^'^  • 

Tibio-tarsal  joint — Perfect  liinge.  On  the  tibia 
a  donble  pulley,  on  the  astragalus,  the  trochlea  of  the 
supero-anterior  faces  ;  two  lateral  external,  three  lat- 
eral internal,  one  anterior  and  one  posterior  ligaments  ; 
the  last  two  are  capsular.  One  synovial  membrane. 
Motions  :  extension  and  flexion. 

Superior  intertarsal  joint — Arthrodia.  Anterior 
face  of  lower  extremity  of  the  os  calcis  and  the  poste- 
rior facettes  of  the  astragalus.  Four  ligaments  :  one 
superior,  one  interosseous,  one  external  and  one  inter- 
nal.    Sliding  motion. 

Tarso  tarsal  joint — Arthrodia.  The  facettes  on  the 
OS  calcis  and  the  inferior  face  of  the  astragalus  above, 
below  tlie  superior  face  pf  the  scaphoid  and  cuboid, 
bix  ligaments :  two  lateral,rone  calcaneo-nietatarsal, 
one  astragaio-metatarsal,  one  posterior  tarso-metatarsal 
and  one  interosseous.  One  synovial  capsula.  Motion 
very  limited. 

Inferior  inter-tarsal  joint — Arthrodia — with  al- 
most no  motion.  On  the  cuboid  two  facettes  for  the 
scaphoid  and  two  for  the  great  cuneiform  ;  on  the  sca- 
phoid, facettes  on  the  inferior  surface  for  both  cunei- 
forms ;    the  two  cuneiforms  have  each  one  small  facet. 


52  EQUINE    ANATOMY. 

Two  anterior  and  two  interosseous-  ligaments,  with  tlie 
astj'agalo-metatarsal  and  posterior  tarso-metatarsal  liga- 
ments are  the  means  of  nnion. 

Tarso-metatarsal  joint — Artlirodia.'  The  infer- 
ior face  of  the  cuboid  and  tlie  two  cuneiforms,  with 
the  three  metatarsi  bones  articulate  by  facettes.  As 
means  of  union  it  offers  the  ligaments  of  the  tibio-tar- 
€al  joint,  the  calcaneo-metatarsal  ligament,  and  the  as- 
tragalo-metatarsal  and  tarso-metatarsal  ligaments.  One 
synovial  capsula.     The  motions  are  nearlj"  null. 

3IY0L0G1. 

Gluteal  Rei?ioii,  or  Region  of  the  Hip,— Three  mus- 
cles. 

1.  Superficial  gluteus. — Synonyms,  llio-trochan- 
terius  medius,  (G).  Gluteus  externus,  (P).  Ilio-tro- 
<ihanterius  externus,  (L).  iVttachments  :  The  internal 
face  of  the  gluteal  aponeurosis,  the  posterior  extremity 
of  the  ischium,  the  ischiatic  ligament,  the  external 
tuberosity  of  the  body  of  the  femur.  Action  :  Al)- 
ductor  of  the  thigh. 

2.  Middle  gluteus. — Synonyms.  Ilio-trochanterius 
magnus,  (G).  Gluteus  magnus,  (P).  Superior  portion 
of  the  great  ilio-trochanterius,  (L).  Attachments  : 
The  internal  face  of  the  gluteal  aponeurosis,  the  super- 
ior face  and  anterior  angle  of  the  ilium,  the  two  ilio- 


EXTREMITIES.  53 

«acral  ligaments,  the  sacro-sciatic  ligament,  and  on  the 
trochanter  of  the  superior  extremity  of  the  femur  by 
three  branches.  Action :  Extensor  and  abductor  of 
the  thityh  and  assists  in  rearino^. 

3.  Deep  gluteus. — Synonyms.  Small  ilio-trochan- 
teriuSj  (G).  Gluteus  parvus,  (P).  Attachments  :  The 
neck  of  the  ilium,  the  supra  cotyloid  crest,  the  inside 
of  the  convexity  of  the  great  trochanter.  Action  : 
Abductor  of  the  thigh,  and  rotator  inward  indirectly. 

Crural  Region,  or  Region  of  the  Thigh.— Division  : 
Anterior,  posterior  and  internal. 

Anterior  Crural  Region. — Three  muscles. 

1.  Muscle  of  the  fascia  lata. — Synonyms.  Ilio- 
tiponeuroticus,  (G).  Tensor  vaginae,  (P).  Ischio  ro- 
tuleus  extermis,  (L).  Attachments  :  External  angle  of 
the  ilium,  external  crest  of  the  femur,  and  to  the 
patella.     Action :  Flexor  of  the  femur. 

2.  Crural  triceps. — Division  :  Anterior  straiglit, 
vastus  externus,  vastus  internus. 

a.  Anterior  straight. — Synonyms.  Ilio-rotuleus, 
{G).  Rectus,  (P).  Anterior  ilio-rotuleus,  (L).  At- 
tachments: By  two  tendous  to  the  rim  of  the  cotyloid 
cavity,  and  to  the  anterior  face  of  the  patella.  Action  ; 
Extensor  of  the  leg  and  flexor  of  the  thigh. 

Ij.  Vastus  externus. — Attachments :  External  face 
and  external  half  of  the  anterior  face  of  the  femur, 


54  EQUINE    ANATOMY. 

superior  face  and  external  border  of  the  patella. 
Action  :  Extensor  of  the  leg:. 

c.  Vastus  internus. — Attachments  :  Internal  face 
and  internal  half  of  the  anterior  face  of  the  femur, 
superior  face  and  internal  border  of  the  patella.  Ac- 
tion :  Extensor  of  the  leg. 

-  3.  Anterior  grele. — Synonyms.  Ilio-femoral  grele. 
(G).  Crureus  vel  cruralis,  (P).  Attachments  :  Rim 
of  the  ilium,  superior  part  of  the  anterior  face  of  the 
femur.  Action :  Raises  the  capsular  ligament  of  the 
coxo-femoral  joint. 

Posterior  trural  Region,— Three  muscles. 

1.  Long  vastus. — Synonyms.  Ischio-tibialis  exter- 
nus,  (G).  Biceps  abductor  femoris,  (P).  Anterior 
pubio-ischio-tibialis,  (L).  Attachments  :  The  anterior 
portion  to  the  sacral  spine,  sacro-sciatic  ligament, 
coccygeal  aponeurosis,  ischial  tuberosity,  behind  the 
sub-trochanterian  crest  and  to  the  anterior  face  of  the 
patella  ;  the  posterior  portion  to  tlie  iscliial  and  the 
tibial  crests.  Action  :  Abductor  of  the  leg  and  ex- 
tensor of  the  tliigh  ;  also  flexes  the  leg,  and  is  a  tensor 
of  the  tibial  aponeurosis. 

2.  Semi-tendinosus. — Synonyms.  Ischio-tibialis  me- 
dius  or  posticus,  (G).  Adductor  tibialis,  (P).  Pos- 
terior sacro-ischio-tibialis,  (L).  Attachments  :  Sacral 
spine,  sacro-ischiatic   ligament,  the   ischial  tuberosity, 


EXTREMITIES.  55 

and  anterior  crest  of  the  tibia.     Action  :  Flexor  of  the 
leg  and  tensor  of  the  tibial  aponeurosis ;  it  also  assists 

in  rearing.  a^:^cCit^^,-±:::::^:^^:f^ , 

3.    Semi-membranosus. — Synonyms.      Ischio-tibialis 

internus,  (G).  Adductor  tibialis,  (F).  Great  ischio- 
femoralis,  (L).  Attachments  :  to  the  coccygeal  apon- 
eurosis, the  ischial  tuberosity,  inferior  face  of  the 
ischium  and  ©sternal  condyle  of  the  femur.  Action  : 
Adductor  of  the  limb,  extensor  of  the  thigh,  and 
assistant  in  rearing. 
Internal  Crural  Region. — Mne  muscles. 

1.  Long  adductor  of  the  leg. — Synonyms.  Sub- 
lumbo-tibialis,  (G).  Sartorius,  (P).  Internal  ilio-rotu- 
leus,  (L).  Attachments:  To  the  iliac  fascia,  near  the 
tendon  of  the  small  psoas  muscle,  and  to  the  internal 
patellar  ligament.  Action  :  Adductor  of  the  leg  and 
flexor  of  the  thigh. 

2.  Short  adductor  of  the  leg. — Synonyms.  Sub- 
pubio-tibialis,  (G).  Gracilis,  (P).  Pubio-tibialis,  (L). 
Attachments  :  Ischio-pubic  symphysis,  internal  patellar 
ligament,  and  the  internal  face  of  the  tibia.  Action  : 
Adductor  of  the  leg  and  tensor  of  the  tibial  aponeu- 
rosis. 

3.  Pectineus. — Synonyms.  Superpubio-femoralis, 
(G).  Anterior  pubio-femoralis,  (L).  Attachments : 
On  the  inferior  face  of  the  pubis,  and  around  the  med- 


56  EQUINE    ANATOMY. 

ullary  foramen  of  tlie  femur.     Action  :  Adductor  and 
flexor  of  the  tliigh  and  rotator  inwards. 

4.  Small  adductor  of  the  thigh. — Synonyms.  Ad- 
diictor  brevis,  (P).  Middle  pnbio-femoralis,  (L)» 
Attachments :  To  the  inferior  face  of  the  pubis,  and  the 
posterior  face  of  the  femur.  Action  ;  Adductor  of  the 
thigh. 

5.  Great  adductor  of  the  thigh. — Synonyms.. 
Adductor  longus,  (P).  Posterior  pubio-femoralis,  (L). 
Attacliments  :  On  the  inferior  face  of  the  ischium,  the 
posterior  face  and  above  the  internal  condyle  of  the 
femur.  Action  :  Adductor,  extensor  and  rotator  out- 
wards of  the  fenuir. 

6.  Square  Crural. — Synonyms.  Ischio-femoral 
grele,  (G).  Not  described  by  P.  Small  ischio-femor- 
alis,  (L).  Attachments  :  In  front  of  the  ischial  tuber- 
osity and  on  the  posterior  face  of  the  femur.  Action  : 
Extensor  and  adductor  of  the  femur. 

7.  External  obturator. — Synonyms.  Subpubio- 
trochanterius  externus,  (G).  Attaclnnents :  On  tlie 
inferior  face  of  the  pubis  and  ischium  and  in  the  tro- 
chanterian  fossa.  Action  :  Adductor  and  rotator  out- 
wards of  the  femur. 

8.  Internal  obturator. — Synonyms.  Subpubio- 
trochanterius  internus,  (G).  Attachments  :  On  the  an- 
terior angle  of  tlie  sacrum,  the  superior  face  of  tlie 


EXTREMITIES. 


57 


•pubis,  around  the  obturator  foramen,  and  in  the  tro- 
chanterian  fossa.  Action :  Kotator  outward  of  the 
thigh,  and  possibly  abductor. 

9.  Gemelli  of  the  pelvis. — Synonyms.  Ischio- 
trochanterius,  (G).  Gemini,  (P).  Bifemoro-calcaneus, 
(L).  Attachments  :  On  the  external  border  of  the  isch- 
ium and  in  the  trochanterian  fossa.  Action  :  Rotator 
outwards  of  the  thigh. 

Tibial  Region,  or  Region  of  the  Leg.— Division  : 
Anterior  and  posterior. 

Anterior  region. — Three  muscles. 

1.  Anterior  extensor  of  the  phalanges. — Syn- 
onyms. Femoro-prephalangeus,  (G).  Extensor  pedis, 
(P).  Attachments :  In  the  digital  fossa,  situated  be- 
tween the  external  condyle  and  the  external  border  of 
the  trochlea  of  tlie  femur,  to  the  capsular  ligament  of 
the  fetlock  joint,  the  anterior  face  of  the  two  first 
phalanges  and  the  pyramidal  eminence  of  the  os  pedis. 
Action :  Extends  the  digits  and  flexes  the  whole  digital 
region. 

2.  Lateral  extensor  of  the  phalanges.— Synonyms, 
Peroneo-prephalangeus,  (G).  Peroneus,  (P).  Tibio- 
prephalangeus,  (L).  Attachments :  On  the  external 
femoro-tibial  ligament,  the  fibula  and  to  the  tendon  of 
the  anterior  extensor.  Action  :  Same  as  the  extensor 
pedis. 


58  EQUINE    ANATOMY.      <OL   ^  >. 

3.  Flexor  of  the  metatarsus. — Synonyms.  Tibio-* 
premetatarsiis,  (G).  Flexor  metatarsi^  (P).  Attach- 
ments :  In  the  fossa  of  the  inferior  extremity  of  the 
femur  with  the  anterior  extensor  pedis,  the  external 
fossa  of  the  tibia,  on  the  anterior  tuberosity  of  the 
superior  extremity  of  the  principal  metatarsal  by  two 
tendons,  to  the  anterior  face  of  the  cuboid  and  to  the 
small  cuneiform.  Action :  Flexor  of  the  foot  on  the 
leg. 

Posterior  region. — Six  muscles. 

1.  Gemelli  of  the  leg  or  gastrocnemii. — Syno- 
nyms. Bifemoro-calcaneus,  (G).  Gastrocnemius  ex- 
ternus,  (P).  Attachments :  By  two  fleshy  bodies  on 
the  rough  edge  of  the  sus-condyloid  fossa,  on  the  in- 
side .of  the  f  emui'^nd  on  ^4^  ^P^^  <^  the  os  calcis. 
Action  :  Extensor  of  the  foot  on  the  tibia.    J  ^^  "- 

2.  SoLEus  OR  SoLEARis. — Syuonyms.  Peroneo-cal- 
caneus,  (G).  Plantaris,  (P).  Attachments:  Supero- 
external  tuberosity  of  the  tibia  and  the  tendon  .of  the 
gastrocnemii.     Action :    Like  the  gemelli  of  the  leg. 

3.  Superficial  flexor  of  the  phalanges.— Synon- 
ym.    Femoro-phalangeus,  (G).     Gastrocnemius  intern- 
nus,  (P).     Attachments:  Sus-condyloid  fossa  and  the 
coronet.     Action  :  Flexes  the  second  phalanx  on  tlie-. 
flrst  and  tliat  on  the  metatarsus. 

4.  PoPLiTEUs. — Synonyms.      Femoro-tibialis    obliq- 


EXTKEMITIZS.  59 

uiis,  (G).  Attachments :  On  the  external  condyle  of 
the  femur,  the  superior  triangular  surface  of  the  pos- 
terior face  of  the  tibia.  Action  :  Flexor  of  the  leg 
and  rotator  inwards. 

5.  Deep  flexor  of  the  phalanges. — Sjnnnyms. 
Tibio-phalangeus,  (G).  Flexor  pedis,  (P).  Great 
tibio-phalangeus,  (L).  Attachments :  The  posterior 
face  of  the  tibia  on  its  lower  triangular  surface,  the 
supero-external  tuberosity  of  the  same  bone,  to  the 
fibula,  the  interosseous  ligament  of  the  tibio -fibular 
joint,  and  the  semilunar  crest  of  the  os  pedis.  Action: 
Flexes  the  phalanges  on  each  other  and  on  the  meta- 
tarsus, and  extends  the  whole  digital  region  on  the 
tibia. 

6.  Oblique  flexor  of  the  phalanges. — Synonyms. 
Peroneo-phalangeus,  (G).  Flexor  pedis  accessorius, 
(F).  Small  tibio-phalangeus,  (L).  Attachments :  To 
the  external  tuberosity  of  the  superior  extremity  of 
the  tibia  and  the  tendon  of  the  flexor  perf orans. 
Action:  Congener  of  the  deep  flexor. 


)f  the  deep  fle:j 
ANGEIOLOGY. 


Arteries. — F^oral^  prplonffatjon    of   the  external 

J  iliac  imd^r^he^^^jgi  crest  between  the  pectineus,  the 

•«a^Oi4«s  and  th"e  p^as  iliacus,  runs  along  the  pectineus 

and  the  vastus  internus,  passes  between  the  two  branches 


*i3> 


\i  '^: 


60  EQUINE    ANATOMY. 

of  the  great  adductor  of  the  thigh,  through  the  pos- 
terior vascular  groove  of  the  femur,  and  to  the  superior 
extremity  of  the  bifemoro-calcaneus  muscle  where  it 
becomes  popliteal.  Its  collateral  branches  are :  1 — The 
prepubic,  rising  with  the  deep  musculara-unnin^  through 
the  crural  ring  on  the  anterior  face  of^thecrural  arch, 
^  l^hohmd  the  nock  9f  thq  vagintuchoatri,  and  terminates  in 
the  posterior  abdominal  and  the  external  pujtic  arteries. 
'  The  posterior  abdominal  runs  forward  between  the 
small  oblique  and  traiisverse  muscles,  of  tlie  abdomen, 
along  the  external  border  of  the  rectus  abdominis, 
w^here  it  ends  by  anastomosis  with  the  anterior  abdom- 


inal;'^ The  external  piAic  descends  on  the  posterior 
wall  of  the  in o:uinal  canal,  at  the  inferior  rinoj  of  which 
it  ends  in  the',  sub-cutaneous  abdominal  and  the  anterior 
dorsal  of  the  penis ;  the  sub-cutaneous  abdominal 
anastomoses  with  its  congener  at  the  umbilicus;  the 
anterior  dorsal  of  the  penis  passes  to  the  superior  bor- 
der of  the  penis  and  ends  in  ascending  branches  to 
the  cavernous  artery,  and  descending  branches  to  the 
erectile  tissue  at  the  extremity  of  the  organ.  In  the 
female,  the  dorsal  of  the  penis  becomes  the  mam- 
mary, distributed  to  the  mammae.  2 — Deep  mus- 
cular, or  profunda,  runs  backward  between  the  psoas- 
iliacus  and  pectineus  muscles,  then  between  the  pec 
tineus  and  the  external  obturator,  under  the  adductor 


EXTREMITIES.  61 

of  the  tbio-b,  behind  the  feraui*,  and  disappears  in  tlie 
crural  mnscles.  3 — The  superficial  muscular,  or  great 
anterior  muscular,  runs  downwards,  outwards  and  for- 
wards, passing  between  the  sartorius,  psoas-magnus  and 
iliacug  muscles,  then  between  the  vastus  internus  and 
the  straight  anterior  muscles,  and  terminates  in  the 
triceps  cruralis.  4 — A  number  of  innominated  branch- 
es, or  small  muscular,  amongst  them  the  nutritive  of 
the  femur.  5 — The  saphena  runs  between  the  two 
adductors  of  the  leg  to  the  internal  face  of  the  limb, 
or  to  the  surface  of  the  gracilis,  where  it  terminates 
in  two  small  branches. 

Popliteal. — Continuation  of  the  femoral ;  it  di- 
rects its  course  downwards  between  the  bodies  of  the 
bifemoro  calcaneus,  under  the  popliteus  muscle  and  at 
the  tibial  arch  terminates  in  the  posterior  and  anterior 
tibial.  Collateral  branches  :  1 — femoro-popliteal,  with 
its  ascending  and  descending  terminal  ramifications ; 
2 — articular  branches  ;  3 — muscular  branches. 

Posterior  tibial. — Situated  under  the  popliteus, 
the  oblique  and  deep  flexors  of  the  phalanges,  it  runs 
down  to  the  hock  joint  and  becomes  more  and  more 
superficial ;  near  the  os  calcis  it  runs  through  the  tibial 
aponeurosis,  passes  into  the  tibial  arch  and  at  the  as- 
tragalus ends  in  the  plantar  arteries.  Collateral 
branches  :   1 — musculo-tibial  branches  ;  2 — the  medul- 


62  EQUINE    ANATOMY. 

lary  artery  of  the  tibia;    3 — tarsal  articular  branches; 
4 — cutaneous  brandies. 

Plantar. — One  each  side  of  the  perforans  tendon, 
thej  run  down  in  the  tarsal  arch  to  the  suspensory 
ligament  and  anastomose  with  the  perforating  pedal 
artery.  Collateral  branches  :  1 — tarsal  articular  ;  2 — 
superficial  arteries  to  the  tendons ;  3 — deep  external 
and  internal  interosseous  plantar  arteries. 

Anterior  tibial. — Runs  through  the  tibial  arcli  on 
the  anterior  face  of  the  tibia,  under  the  flexor  metatarsi, 
and  at  the  tibio-tarsal  joint  becomes  the  pedal,  after 
sendins:  off  collateral  muscular  branches. 

Pedal. — Passes  in  front  of  the  hock  joint,  bending 
outwards,  and  on  a  level  with  the  lower  row  of  bones, 
divides  into  perforating  pedal  and  metatarso-pedal 
arteries. 

Perforating  pedal. — Runs  through  the  hock  joint 
and  anastomoses  posteriorly  with  the  plantar  artery  of 
the  posterior  tibial. 

Metatarso-pedal. — Passes  in  the  fissure  outside  of 
the  large  metatarsal  bone,  forward  of  the  external 
rudimentary  one,  then  to  the  posterior  face  of  the  first 
named  bone  above  the  sesamoid  groove,  and  terminates 
in  the  collaterals  of  the  digit  or  the  digital  arteries. 
Collateral  branches  are  tendinous,  ligamentous,  cutane- 
ous and  articular. 


EXTKEMlTiES.  63 

Digital. — (See  the  anterior  extremity,  page  33). 

Veios* — Tiie  subuno^ueal  network  from  wliicli  rises 
tlie  two  digital  veins.  To  these  succeed  three  meta- 
tarsal veins,  common  origin  of  all  the  veins  of  the  leg. 
These  are  divided  into  superficial  and  deep ;  two  su- 
j)erficial — the  saphena,  and  two  deep — the  tibial.  All 
empty  in  the  popliteal,  which  is  continued  by  the 
femoral,  and  this  by  the  external  iliac,  which  re- 
ceives only  one  important  vein,  viz. — the  circumflex 
iliac.  The  external  iliac  vein  uniting  with  the  internal 
iliac  form  the  primitive  iliac  or  pelvi-crural  trunk, 
which  empties  into  the  posterior  vena  cava. 

Lymphatics. — They  all  converge  towards  the  sub- 
lumbar  ganglions  and  present  in  their  extent  other 
ganglionary  masses  constituting  the  deep  and  super- 
ficial ingunial,  popliteal,  iliac,  and  precrural  ganglions, 
to  each  of  which  afferent  lymphatic  vessels  arrive,  and 
from  which  efferent  vessels  are  given  off. 

NEUROLOGY. 

Lumbar  Plexus.— Formed  by  the  two  last  lumbar 
and  three  first  sacral  pairs  of  nerves,  is  divided  into 
anterior  and  posterior  portions.  The  first  is  concealed 
by  the  small  psoas  muscle,  and  lies  in  front  of  the 
internal  iliac  artery.  The  posterior,  on  a  level  with 
the  great  sciatic  notch,  is  in  connection  inwards  with 


64 


EQUINE    ANATOMY, 


psoas  mns- 


Vi 


tlie  subsacral  blood  vessels,  outwards  and  in  front  with 
the  gluteal  vessels.  The  anterior  portion  ends  in  the 
<irural  and  obturator  nerves,  and  gives  off  the  iliaco- 
muscular.  The  posterior  is  continued  by  the  great 
sciatic  and  external  popliteal-sciatic  nerves,  after  giving 
■off  the  small  sciatic  including  the  anterior  and  posterior 

^■^^frftiAtJO-mjscuLAR. — Ramifying  in  the  ps 
-cles. 

2.  Crural  or  anterior  femoral. — Descends  be- 
tween the  small  and  the  great  psoas  to  terminate  in 
the  triceps  cruralis  muscle.  Collateral  branches :  Ac- 
cessory of  the  internal  saphena  and  the  internal  saphena, 
both  becoming  sub-cutaneous  before  terminating. 

3.  Obturator. — Runs  alongside  the  obturator  artery 
under  the  internal  obturator  muscle  throuo^h  the  obtu- 
rator  foramen,  and   ramifies  in    the   deep  muscles  of 

w^l  the  internal  crural  region. 

4.  Small  sciatic  or  anterior  and  posterior  glu- 
teal.— Anterior  gluteal  or  ilio-rauscular :  Four  or 
five  branches  from  the  two  first  sacral  pairs,  going  to 
the  middle  gluteus  muscle.  Posterior  gluteal  or  ischio- 
muscular  :  Two  in  number  ;  one,  superior,  goes  to  the 
long  vastus ;  and  one,  inferior,  passes  under  that  muscle, 
and  the  semitendinosus  towards  the  ischial  tuberosity, 
where  it  ends  in  cutaneous  branches. 


extremities.  65 

5,  Great  sciatic,  or  great  femoro-popliteal. — 
Passes  tlirouo^h  tlie  2:reat  sciatic  notch  outside  the  isclii- 
atic  ligament,  over  the  small  glutens,  behind  the 
gemelli  of  the  pelvis  and  the  square  crural,  bends 
downwards  behind  the  femur  in  front  of  the  ischio- 
tibial  muscles,  passes  between  the  bellies  of  the 
bifemoro-calcaneus,  behind  the  perforatus,  reaches  the 
hock,  and  at  the  os  calcis  divides  into  the  external  and 
internal  plantar  nerves.  Collateral  branches  :  1 — The 
external  sciatic-popliteal,  or  small  femoro-popliteal, 
runs  forwards  and  downwards  between  the  long  vastus 
and  the  gastrocnemius  externus,  and  on  the  outside 
of  the  superior  extremity  of  the  leg  terminates  in  the 
musculo-cutaneous  and  anterior  tibial  branches.  The 
musculo-cutaneous  passes  under  the  tibial  aponeurosis 
between  the  anterior  and  lateral  extensors  of  the  pha- 
langes, becoming  subcutaneous  to  terminate.  The 
anterior  tibial  runs  under  the  anterior  extensor  pedis 
to  the  front  of  the  hock,  with  the  pedal  artery  down 
to  the  fetlock,  where  it  ends  by  cutaneous  filaments. 
2 — Branches  to  the  deep  muscles  of  the  internal  crural 
region.  Leaving  the  sciatic  at  the  middle  of  the  supra- 
cutyloid  crest,  these  branches  pass  behind  the  coxo- 
femoral  joint  and  branch  off  to  the  muscles.  3 — 
Branches  to  the  posterior  crural  muscles,  rising  from 
the  sciatic  at  the  gemelli  muscles,  and  then  te.'minating 


\ 


66  EQUINE    ANATOMY, 

by  several  ramifications.  4 — The  external  saphena 
passes  over  the  external  body  of  the  bifemoro-calca- 
neoiis,  downwards  to  the  origin  of  the  tendo-Achillis, 
on  the  outside  of  which  it  passes  over  to  the  tarsus 
and  terminates  in  the  metatarsus.  5 — Branches  to 
the  posterior  tibial  muscles,  several  in  number,  coming 
from  the  sciatic  as  it  passes  between  the  gemelli  of 
the  leg,  and  then  ramifying  in  these  muscles.  6 — Cuta- 
neous branch  as  it  runs  along  the  tendo-Achillis. 

Jt^LANTAR. — Situated  in  the  tarsal  sheath,  behind  the 
perforans  tendon,  they  reach  the  upper  extremity  of 
the  metatarsus,  and  separating  from  each  other  run  on 
each  side  of  the  tendons  of  the  deep  fl.exors  to  the 
fetlock  joint,  and  terminate  as  those  of  the  anterior 
extremity. 


CHAPTER    lY. 


HLE^D. 


OSTEOLOGY. 

The  HEAD  is  divided  into  cranium  and  face. 

Cranium. — Division  :  Seven  bones — occipital,  pari- 
etal, frontal,  ethmoid,  sphenoid  and  two  temporals. 

Occipital. — Division :  Two  faces  and  a  circum- 
ference. External  face  is  divided  into  three  parts. 
Presents  parietal  crest,  occipital  protuberance,  cervical 
tuberosity,  occipital  foramen,  basilar  process,  mastoid 
crest,  muscular  imprints,  condyles,  styloid  process,  notch, 
condyloid  fossa  and  foramen.  Internal  face,  concave, 
forming  the  posterior  cavity  of  the  cranium.  Cb*cum- 
ference  is  divided  into  two  anterior  and  two  posterior 
lateral  borders,  joined  by  four  angles.  Development; 
four  nuclei  of  ossification. 

Parietal. — Division  :  Two  faces  and  four  borders. 
External  face  is  convex,  and  shows  the  parietal  crest 


68  EQUINE    ANATOMY. 

Internal  face  has  digital  marks,  and  the  internal  parietal 
protuberance.  The  borders  are  dirided  into  superior, 
inferior  and  lateral,  and  are  articular.  Development : 
three  nuclei  of  ossification. 

Fkontal. — Division  :  Two  faces  and  four  borders. 
External  face  divided  into  three  parts,  shows  the 
orbital  process,  the  supra-orbital  foramen,  and  a  cavity 
for  the  internal  oblique  muscle  of  the  eye.  Internal 
face  is  also  divided  into  two  parts,  superiorly  has  a 
median  crest  and  a  notch  for  the  sphenoid  ;  inferiorly 
it  opens  in  the  frontal  sinuses.  Borders  :  the  superior 
articulates  with  the  parietal,  the  inferior  with  the  nasal 
and  lachrymal,  the  lateral  has  a  superior  notch  for  the 
sphenoid,  and  one  inferior  for  the  orbital  foramen. 
Development :   two  nuclei  of  ossification. 

Ethmoid. — Division :  Perpendicular  lamina  and 
two  lateral  masses.  Perpendicular  lamina :  Two 
faces,  flat ;  four  borders  :  the  superior  forms  the  crista- 
galli  process ;  the  inferior,  continuous  with  the  septum 
nasi ;  the  anterior,  with  the  septum  of  the  frontal 
sinuses ;  the  posterior,  with  that  of  the  sphenoidal 
sinuses.  Lateral  masses. — Division  :  Middle  part,  base 
and  apex.  The  external  surface  of  the  first  is  divided 
into  external  and  internal  portions;  the  internal  sur- 
face forms  the  cavities  of  the  volutes.  Tlie  base  has 
the  cribriform  plate  and  the  ethmoidal  fossa.     The 


HEAD.  69 

apex  forms  the  inferior  extremity  of  the  cells.  Devel- 
opment: three  nuclei  of  ossification. 

Sphenoid. — Division  :  Body  and  wings,  two  faces 
and  four  borders.  The  external  surface,  continned 
with  the  basilar  process,  shows  the  vidian  fissure,  tlie 
vidian  canal,  the  sub-sphenoidal  canals,  the  orbital 
hiatus,  a  surface  for  the  orbital  cavity.  The  internal 
face  shows  the  crista-galli  process,  the  optic  fossa,  tlie 
pituitary  fossa,  some  digital  impressions,  mastoid  fossa^ 
two  fissures — one  internal  cavernous,  and  one  external, 
both  opening  in  the  three  super-sphenoidal  canals  form- 
ing the  foramen  lacerum  orbitale,the  foramen  rotunduni 
magnum  and  the  foramen  patheticum.  The  borders 
are :  superior,  articulated  wdth  tlie  occipital,  and  pre- 
senting three  notches — one  internal,  the  carotid,  contin- 
uous with  the  carotid  fossa,  one  external,  for  the  infer- 
ior maxillary  nerve,  and  one  outward,  for  the  middle 
meningeal  artery ;  an  inferior  border  assists  to  form  tlie 
sphenoidal  sinus;  two  lateral  borders,  articulated  with 
the  frontal.     Development :    two  nuclei  of  ossification. 

Temporal. — Division  :  Squamous  and  tuberous  por- 
tions. 

Squamous. — Two  faces  and  a  circumference.  The 
external  face  shows  the  zygomatic  process  with  a  base 
having  a  condyle  and  a  glenoid  cavity,  an  external  and 
an  internal  face,  and  an  apex ;  the  internal  face  has  a 


70  EQDLNE    ANATOMY. 

groove  for  the  parieto-temporal  caual.  The  circum- 
ference is  divided  into  an  anterior  and  posterior  border. 
Development :  one  nucleus  of  ossification. 

Tuberous. — Four  faces,  four  borders,  a  base  and  an 
apex.  The  faces  are  articular,  except  the  internal, 
whicli  offers  the  internal  auditory  hiatus,  the  internal 
opening  of  the  aqueduct  of  Fallopius.  Of  the  borders, 
one,  the  postero-external,  forms  the  mastoid  crest  and 
the  mastoid  process ;  another,  the  antero-iuternal,  gives 
attachments  to  the  tentorium  cerebelli.  The  apex  is 
articular.  The  base  shows  the  external  auditory  hiatus, 
the  stylo-mastoid  foramen,  a  sharp  subuliform  process, 
the  mastoid  protuberance,  and  hyoid  process.  Devel- 
opment !  two  nuclei  of  ossification. 

Face — Division:  Superior  jaw,  nineteen  bones — 
great  superior  maxillary,  small  superior  maxillary, 
nasal,  lachrymal,  zygomatic,  palate,  pterygoid,  nasal 
and  maxillary  turbinated,  and  vomer.  Inferior  jaw, 
one  bone — the  inferior  maxillary. 

Great  super-maxillary. — Division :  Two  faces, 
two  borders,  and  two  extremities.  The  external  face 
presents  the  maxillary  spine  and  the  inferior  open- 
ing of  the  super-maxillo-dental  canal ;  the  internal 
face  is  a  part  of  the  maxillary  sinus,  and  exhibits  the 
palatine  duct,  a  crest  for  attacliment  of  the  maxillary 
turbinated,  the  palatine  process  and  the  palatine  fis- 


HEAD. 


71 


sure.  The  anterior  border  is  articular ;  the  posterior 
has  the  alveolar  cavities,  the  alveolar  tuberosity  and 
the  inter-dental  space.  The  superior  extremity  forms 
the  maxillary  hiatus,  with  three  openings,  the  nasal 
foramen,  super-maxillo  dental  canal,  and  palatine  canal. 
The  inferior  extremity  has  an  alveolus  for  the  tusk. 
Development :  one  nucleus  of  ossification. 

Pre-maxillaky,  or  small  maxillary. — Division : 
One  body  and  two  processes.  Body  has  three  faces — 
the  external,  or  labial,  the  internal  with  a  notch  to 
form  the  incisive  canal,  and  the  posterior  or  buccal. 
Of  the  three  borders,  two  are  internal,  the  external 
has  three  alveoli  for  the  incisive  teeth  and  one  notch 
for  the  tusk,  between  the\  the  interdental  space. 
Processes :  the  external  is  the  longest  and  has  two 
faces,  two  borders  and  an  apex  ;  the  internal  forms 
the  incisive  cleft  or  opening.  Development :  one 
nucleus  of  ossification. 

Palate. — Division :  Two  faces,  two  borders  and 
two  extremities.  The  external  face  has  three  regions, 
one  superior  or  orbital  with  the  staphyloid  groove,  one 
inferior,  forming  the  roof  of  the  palate,  and  one  mid- 
dle, articular.  The  internal  face  belongs  to  the  nasal 
cavities.  The  anterior  border  has  the  nasal  foramen, 
the  posterior  the  palatine  crest.  The  superior  extremi- 
ty articulates  with  the  sphenoid,  the  inferior  with  that 


72 


EQUINE    ANATOMY. 


of  the  opposite  side.     Development :    one  nucleus  of 
ossification. 

Pterygoid. — Two  faces  and  two  extremities  ;  the  in- 
ferior extremity  has  a  tendinous  pulley.  Develop- 
ment: one  nucleus  of  ossification. 

Zygomatic. — Division :  Two  faces^  two  borders,  a 
base  and  an  apex.  The  external  face  has  two  portions, 
one  anterior  orbital,  one  posterior  convex ;  the  in- 
ternal face  forms  the  maxillary  sinuses.  The  anterior 
border  is  articular,  the  posterior  shows  the  zygomatic 
crest ;  the  base  is  articular,  the  apex  at  the  zygomatic 
arch  forms  the  jugal  bridge.  Development :  one 
nucleus  of  ossification. 

Lachrymal. — Division  :  Two  faces  and  a  circum- 
ference. The  external  face  has  two  regions,  one  su- 
perior or  orbital,  w^ith  the  orifice  of  the  lachrymal 
duct  and  the  lachrymal  fossa,  and  one  inferior  or  facial 
with  tlie  lachrymal  tubercle.  The  internal  face  forms 
the  maxillary  and  frontal  sinuses.  The  circumference 
is  articular.     Development :    one  nucleus. 

Nasal. — Two  faces,  two  borders,  abase  and  an  apex. 
Tiie  external  face  is  smooth;  the  internal  or  pos- 
terior has  a  crest  for  the  turbinated  bone.  The  ex- 
ternal border  articulates  above,  but  is  free  below  to 
form  the  nasal  spine ;  the  internal  is  articular,  as  is  the 
base.     Development :  one  nucleus  of  ossification. 


HEAD.  73 

Turbinated  Bones. — Tlie  anterior,  superior  or 
ethmoidal,  and  posterior  or  maxillarv.  The  internal 
surface  is  divided  by  transverse  plates ;  between 
these  and  the  surrounding  bones  are  found  the 
three  meatuses.  Development  :  one  nucleus  for 
each. 

YoMER. — Has  two  faces,  smooth,  an  anterior  border 
grooved,  and  a  posterior  sharp  superiorly,  thick  and  ar- 
ticular inferiorly  ;  an  anterior  extremity  going  to  the 
incisive  slit,  and  a  posterior  notched  and  articular. 
Development:  one  nucleus  of  ossification. 

Inferior  Maxillary. — Division :  Two  faces,  two  boi'- 
ders  and  two  extremities.  External  face  half  smooth  and 
half  rough,  shows  below  the  mental  foramen  ;  internal 
face  shows  the  maxillo-dental  canal,  the  myloid  ridge 
and  the  glenoid  surface.  The  anterior  border  is 
alveolar  and  divided  into  two  parts;  the  posterior 
border  has  also  two  parts,  and  offers  tlie  maxillary 
fissure  and  maxillary  tuberosity.  The  superior  extrem- 
ity has  a  condyle,  coronoid  process  and  corono-condy- 
loid  notch  ;  the  inferior  forms  the  body,  with  an  anter- 
ior face,  buccal,  and  a  posterior,  labial.  Its  circumfer- 
ence has  the  alveoli  for  the  incisive  teeth.  The  neck 
of  the  bone  is  at  the  iunction  of  the  two  branches. 
Development :  two  nuclei  of  ossification. 


74  EQUINE  ANATOMY. 

SYIVDESIWOLOGY. 

Temporo-maxillary  joint— Double  condyloid.  On 
the  temporal,  a  condyle,  glenoid  cavity  and  snpra-con- 
dyloid  process ;  on  the  raaxillary,  a  condyle,  inter- 
articiilar  meniscus,  capsula**  ligament.  Motions  :  De- 
pression, elevation,  lateral  motion,  horizontal  gliding. 

Otlier  joints  are  all  synarthrodial,  sutura. 

MYOLOGY. 

Facial  Region,— Thirteen  muscles. 

1.  Lawai^is. — Synonyms.  Orbicularis  oris,  (P). 
Attachments  :  Ko  bony  attachments.  Action  :  Con- 
strictor of  the  lips. 

2.  Alveolo-labialis. — Synon^ans.    Buccinator,  (P). 
Buccinator  and  molaris,  (L).     Attachments  :  Alveolar 
tuberosity,  superior  and  inferior /maxijlary.     Action  : 
Belated  to  mastication.  ^^<*<^^  Q^^^  ^    ' 

ABiALis,-— Synonyms.    Zysiamaticus, 
3 :  burracejor  the  mas^ei'^and  com- 


3.  Zygomatico-labialis,- 
(P).     Attachments' 
missure   of  the  lips.     Action :  Pulls  the  commissure 
backwards. 

4.  Lachrymo-labialis. — Synonyms.  Not  mentioned 
by  P.  Inferior  palpebral,  (L).  Attachments:  Lach- 
rymal and  zyo'omatic'bones,  cellulau  fasciafj30verin2r  the 
alveolo-labialis.-^  Action :  Corrugates  tlie  skin  below 
tl^e  eye.  j>    0   '    0' 


HEAD.  75 

5.  SuPERNASO-LABiALis. — SynonjiTis.  Levator  labii 
siiperioris  alceque  nasi,  (P).  Fronto-labialis,  (L).  At- 
tachments :  Frontal  and  nasal  bones,  external  alae  of 
the  nose  and  commissure  of  the  lips.  Action :  Elevates 
the  alee  of  the  nose,  the  upper  lip  and  tlie  commissure. 

6.  StiPER-MAxiLLO-LABiALis. — Sjuonyms.  Nasalis 
longns  labii  siiperioris,  (P).  Attachments :  Super- 
maxillary  and  zygomatic  bones  to  upper  lip  with  its 
congener.  Action  :  Raises  the  upper  lip  directly  or 
sideways. 

T.  Great  suPER-MAxiLLO-NASALis.-Synonyms.  Dila- 
tator naris  lateralis,  (P).  Attachments  :  The  external 
face  of  the  superior  maxillary  and  the  external  wing 
of  the  nostril.  Action :  Dilates  the  external  orifice 
of  the  nasal  cavity. 

8.  Small  super-maxillo  nasalis. — Synonyms.  Na- 
salis  brevis  labii  superioris,  (P).  Attachments  :  The 
premaxillary  bone,  the  nasal  spine,  and  the  skin  of 
the  false  nostrils,  which  it  dilates. 

9.  Transversalis  nasi. — Synonyms.  Dilatator  naris 
anterior,  (P),  Attachments  :  Nasal  cartilages.  Action : 
Dilatator  of  the  nostrils. 

10.  Middle  (intermediate)  anterior. — Synonyms. 
Depressor  labii  superioris,  (P).  Incisive  muscle  of  the 
upper  lip,  (L).  Attachments  :  The  pre-maxillary,  and 
anterior    appendix   of    the  inferior  turbinated   bone. 


76  EQUINE    AN^ATOMY. 

Action :  Dilatator  of  the   entrance  of  the  nasal  fossa. 

11.  Maxtllo-labialis.  Synonyms.  Depressor  labii 
inferioris,  (P).  Inferior  maxillo  labialis,  (L).  Attach- 
ments :  Anterior  border  of  the  lower  jaw  and  the  skin 
of  the  lower  lip.  Action  :  Pulls  the  lower  lip  down 
directly  or  on  one  side. 

12.  Mento-labialis. — Forms  the  base  of  the  ronnded 
protuberance  beneath  the  lower  lip.  No  bony  attach- 
ment. 

13.  Middle  (intermediate)  posterior. — Synonyms. 
Levator  menti,  (P).  Incisive  muscle  of  the  lower  lip. 
(L).  Attachments  :  External  surface  of  the  body  of 
the  lower  jaw  and  to  the  mento-labialis.  Action  : 
Elevator  of  the  lower  lip. 

Masseterine  Region.— Five  muscles. 

1.  Masseter. — Synonyms.  Zygomatico-maxillaris, 
(G:).  Attachments :  Zygomatic  crest,  upper  half  of 
external  surface  of  inferior  maxillary  branch.  Action: 
Elevator  of  the  lower  jaw. 

2.  Temporal. — Synonyms.  Temporo-m axillaris,  (G). 
Attachments :  Temporal  fossa,  orbital  hiatus,  coronoid 
process  and  anterior  border  of  the  branch  of  the  lower 
jaw.     Action  :  Elevates  the  jaw. 

3.  Internal  pterygoid. — Synonyms.  Pterygoid- 
eus  internus,  (P).  Attachments :  The  palatine  crest, 
subsphenoidal  process,  hollow  of  the  internal  face  of  the 


HEAD.  77 

brand)  of  the  lower  maxillary.    Action :  Elevates  and 
moves  the  jaw  laterally. 

4.  External  pterygoideus. — Attachments  :  Inferi- 
or  face  of  the  sphenoid,  subsphenoidal  crest,  neck  of 
the  condyle  of  the  inferior  maxillary.  Action  :  Pulls 
the  maxilla  forward  directly  or  sideways. 

5.  DiGASTRicus. — Synonyms.  Stylo-maxillaris,  (G). 
Attachments :  Styloid  process  of  the  occipital,  curved 
portion  of  the  lower  maxilla,  internal  face  of  same 
bone,  and  straight  portion  of  its  posterior  border. 
Action  :  Fulls  the  jaw  backwards,  and  at  the  same 
time  depresses  it. 

SPLAIVTMOLOGY. 

IVasal  Cavities.^ IS'umber,  two.  Division  :  Nostrils, 
nasal  fossa  proper  and  sinuses. 

Nostrils. — Two  lips  or  borders  united  by  two  com- 
missures. The  superior  commissure  shows  the  false 
nostrils  ;  the  inferior  the  opening  of  the  lachrymal  duct. 
Structure:  cartilages;  muscles, viz:  the transversalis nasi, 
pyramidalis  nasi,  super-maxillo-nasalis  parvus,  middle 
anterior,  and  supernaso-labialis ;  integuments;  blood 
vessels,  viz  :  superior  coronary,  nasal  and  palato-labial 
arteries ;  nerves,  branches  of  tlie  fifth  and  seventh 
cranial  pairs. 

Nasal  foss^  proper. — Divisions :  Four  walls  and 


'%* 


78 


EQUINE    ANATOMY. 


two  extremities*  The  superior  wall  or  roof  ;  the  in- 
ferior or  floor  with  Jacobson's  apparatus  ;  the  lateral 
external  with  the  turbinated  bones  and  meatuses  ;  the 
middle  meatus  having  an  opening  of  communication 
with  the  sinuses ;  the  lateral  internal  is  formed  by 
the  septum  nasi.  The  anterior  extremity  forms  tlie 
nostrils  ;  the  posterior  looks  into  the  pharynx.  Struc- 
ture :  nasal,  maxillary,  frontal,  palate,  ethmoid  and 
turbinated  bones,  middle  septum  of  the  nose ;  pituit- 
ary membrane;  blood  vessels,  the  ophthalmic  and 
nasal  arteries ;  nerves,  first  and  fifth  pairs  of  cranial 
nerves. 

Sinuses. — Five:  the  frontal,  sphenoidal,  ethmoidal 
and  two  maxillary.  All  communicate  through  the 
middle  meatus.  The  inferior  maxillary  sinus  opens 
by  itself  into  the  nasal  fossa.  They  are  all  lined  by 
mucous  membrane  and  develop  with  age. 

Buccal  Cavity. — Division  :  Six  regions. 

a.  Lips.  Superior  and  inferior,  united  by  com- 
missures. Two  faces;  two  borders,  one  adherent 
and  one  free.  Structure :  skin,  mucous  membrane, 
muscles,  viz:  tlie  orbicularis,  super-maxillo  labialis, 
super-naso  labialis,  great  super-maxillo  nasalis,  tufts 
•of  the  chin  and  posterior  intermediate ;  glands,  the 
labial ;  blood  vessels,  the  palato-labial  and  coronary 
arteries ;  nerves,  the  fifth  and  seventh  cranial  pairs. 


HEAD.  79" 

h.  Cheeks.  Two  faces,  on  the  internal  the  opening 
of  Stenon  duct.  Structure:  skin,  mucous  membrane; 
muscles,  viz:  the  alveolo-labialis,  and  the  masseter; 
blood  vessels,  the  maxillary,  coronary  and  buccal 
arteries ;  nerves,  the  fifth  and  seventh  pairs  of  cra- 
nial nerves. 

c.  Palate.  Its  face  is  covered  with  about  twenty 
furrows  curved  backwards.  Structure :  bone,  the  pa- 
late and  great  maxillary;  membranes,  one  fibrous,  one 
mucous ;  vessels,  the  palato-labial  artery  ;  nerves,  fifth 
pair  of  cranial  nerves. 

d.  Tongue. — Situated  in  the  lingual  canal  and  at- 
tached to  tlie  hyoid  apparatus. 

Hyoid  apparatus,  hyoid  bone. — Formed  of  seven 
pieces,  a  body  and  three  branches.  The  body  has  an 
anterior  process  or  spur,  and  two  lateral  branches.  It 
is  developed  by  three  nuclei  of  ossification.  The 
branches;  two  small,  with  articular  facets  at  both  ex- 
tremities ;  two  long,  with  faces  smooth ;  an  anterior 
and  posterior  border ;  one  inferior  extremity  articulated 
with  the  middle  nucleus  or  third  branch ;  one  superior 
articulated  with  the  temporal  bone. 

Muscles. — Five  in  pairs,  and  one  single. 

1.  Mylo-hyoideus. — Attached  to  mylo-hyoid  line  of 
the  inferior  maxillary,  to  anterior  appendix  of  the  body 
of  the  hyoid  bone,  which  it  eleva 


L'^ 


"'^in^^^.^-^TX'^  ^i^M^0L4i^A^ 


80         jU^'^^'^'^^^     EQUlf^^Tl^r^. 

2.  Genio-hyoideus. — Attached  to  the  genial  surface 
and  to  the  anterior  opening  of  the  body  of  the  hyoid 
bone  which  it  draws  forward. 

3.  Stylo-hyoideus — Synonyms.  Hyoidens  magnus, 
(P).  Kerato-hyoideus  magnus,  (L).  Attached  to 
the  supero-posterior  angle  of  the  long  branch,  to  the 
cornua  of  the  os  hyoides,  which  it  draws  backwards. 

4.  Kerato-hyoideus. — Synonyms.  Hyoideus  par- 
vus, (P).     Small  kerato-hyoideus,   (L).     Attached   to 

Vj    the  posterior  border  of  the  cornu^and  the  extremity  of 
-J  the  styloid  bone,  toSie  superior  border  of  the  thyroid 

wino-.     Action:  Brini>;s  the  two  branches  too^ether. 
\^  5.  OcciPiTO-HYOiDEUs. — Attached  to  the  styloid  pro- 

cess of  the  occipital,  the  superior  border  of  the  long 
branch  of  the  hyoid.  Action :  Swings  the  bone  down- 
wards and  backwards. 

6.  Transversalis-hyoideus. — Attachments:  Supe- 
rior extremity  of  the  small  branches.  Action  :  Brings 
them  together. 

External  coneormation  of  the  tongue. — Three 
faces,  three  borders  and  two  extremities.  Superior  face, 
papillae,  foramen  coecum  of  Morgagni ;  lateral  faces, 
large  papilla  and  opening  of  the  lingual  glands.  The 
two  superior  borders  are  thick;  the  inferior  is  fixed  at 
the  bottom  of  the  intermaxillary  space ;  the  anterior 
extremity  or  free  part  is  attached  to  the  maxillary  by 


the  anterior  pillar  or  froenum  linguae ;  the  posterior 
extremity  shows  a  median  mucous  fold  going  to  tlie 
epiglottic  cartilage ;  two  lateral  folds  called  the  pos- 
terior pillars  of  the  tonp*ue,  and  the  amvij-dalpidfcavi- 
ties.  Structure  :  mucous  membrane  with  hlifonu,  '^f^ ^ 
X-fungiform  and  calciform  papillse.     Muscles  :  five.  ^ 

1.  Stylo-glossus. — Synonyms.  Hyo-glossus  longns, 
(P).  Kerato-giossus  externus,  (L).  Attachments : 
External  surface  of  the  long  branch  of  the  hyoid  and 
near  the  tip  of  the  tongue.  Action :  Fulls  the  tongue 
backwards  or  sideways. 

2.  Great  hyo  or  basio-glossus. — Synonyms.  Hyo- 
glossus  brevis,  (P).  Hyo-glossus,  (L).  Attachments : 
The  extremity  of  the  cornu  and  the  anterior  apex  of 
the  hyoid  bone  to  near  the  superior  face  of  the  tongue, 
which  it  retracts.    ^^^^^^^  — j  /C-^t^t^ 

3.  Genio-glossus. — Synonyms.  Genio  hyo-glossus, 
(P).  Attached  to  the  lower  jaw  near  the  symphysis, 
and  to  the  upper  surface  of  the  tongue.  Action : 
Carries  the  tongue  forwards,  backwards  and  down- 
wards in  the  buccal  cavity. 

4.  Small  hyo-glossus. — Synonyms :  Lingualis,  (P). 
Attachments:  Inner  side  of  the  articulation  of  the  two 
branches  of  the  hyoid  bone,  to  the  superior  face  and 
sides  of  the  tona'ue.     Action  :   Contracts  and  retracts 


C^-^ 


W^^r^^ 


82  EQUINE    ANATOMY. 

5.  Fharyngo-glossus. — Attachments  :  The  lateral 
walls  of  the  pharynx  and  posterior  part  of  the  tongue. 
Glands :  racemose  and  follicular.  Blood  vessels,  the 
lingual  and  sub-lingual  arteries.  Nerves,  the  lingual, 
glosso-pharyngual  and  gre^^t  hypo-glossus. 

e.  Soft  Palate — Velum  pendulum  palati. — Two 
faces  :  the  anterior  united  to  the  tongue  by  the  poste- 
rior pillars  of  that  organ;  the  posterior  or  pharyngeal 
with  longitudinal  ridges.  Two  lateral  borders:  one 
anterior,  all  attached  on  bones ;  one  posterior  border, 
embracing  the  epiglottic  cartilage  with  the  two  poste- 
rior folds,  forming  the  posterior  pillars  of  the  velum 
palati.  It  closes  the  isthmus  of  the  fauces.  Structure: 
a  fibrous  membrane  and  four  muscles : 

1 .  Pharyngo-staphyleus. — Synonyms.  Palato-sta- 
phyleus,  (P).  Attachments :  Coiitinujpus  to  the  fi^'ous 
membrane. T^^ct&f Tofretcnes  the  velum  palati. 

2.  Palato-staphyleus. — Synonyms.  Staphyleus,(G). 
Circumflex  palati,  (P).  Attaclied  to  the  palatine  arch 
and  the  free  border  of  the  septum,  which  it  raises. 

3.  Perystaphyleus  externus. — Synonyms.  Ten- 
sor palati,  (P).  Attachments  :  The  styloid  process  of 
the  temporal,  and  fibrous  layer  of  the  velum  palati. 
Action  :  Tensor  and  depressor. 

4.  Perystaphyleus  internus. — Synonyms.  Stylo- 
pharyngeus,  (P).    Attachments:  Same  as  above.    Act- 


HEAD. 


83 


ion:  Elevator  of  the  soft  palate.  Glands:  situated 
on  the  anterior  face  directly  under  the  mucous  mem- 
brane. Mucous  membranes :  two  in  number,  one  on 
the  anterior  and  one  on  the  posterior  face.  Blood  ves- 
sels, the  pharyngeal  and  staphyline  arteries.  Nerves, 
fifth  pair  of  cranial  nerves  and  ganglion  of  Meckel. 

y.  Teeth. — Definition  :  passive  organs  of  mastication. 

General  characters:  general  disposition  form  two 
parabolic  arches  interrupted  on  each  side  by  interdental 
space.  These  arches  present  the  incisive  teeth  in  front, 
the  tusks  behind  them,  and  the  molars  in  the  lateral 
and  posterior  parts  of  the  dental  arches.  External 
conformation  :  they  have  a  root  or  fang  encased  in  an 
alveolus,  and  a  crown  exposed.  Structure :  Ivory  or 
dentine  forming  the  base  of  the  tooth,  and  surrounds 
the  internal  cavity  wdiich  is  filled  by  the  pulp ;  it  is 
hollowed  with  canaliculi,  imbeded  in  amorphous  mat- 
ter. Enamel  forms  the  outside  covering  of  the  free 
part  of  the  tooth,  consisting  of  little  prismatic  hexag- 
onal rods  denticulated  on  theii*  faces.  Cement  irregu- 
larly spread  over  both  the  ivory  and  enamel,  with 
the  structure  and  properties  of  spongy  bone-substance. 
Dental  pulp,  fibrillar  and  nuclear  mass  filling  the  in- 
ternal dental  cavity,  and  receiving  blood  vessels  and 
nerves.  The  gum,  a  portion  of  the  buccal  mucous 
membrane,    surrounds  the   neck   of    the  tootii.      An 


84  EQUINE    ANATOMY. 

alveolar  dental  periosteum  lines  the  cavity  of  tlie  alve- 
olus and  the  external  face  of  the  cement  of  the  fang. 
Development :  the  dental  follicle,  or  a  membrane  con- 
taining at  its  bottom  the  dental  pulp  and  having  in  its 
upper  part  the  enamel  germ,  attached  to  the  guber- 
naculum  dentis.  Considering  their  epoch  of  develop- 
ment, teeth  are  divided  into  caducous,  temporary  or 
milk,  and  replacing  or  persistent  teeth. 

Incisors. — Six  in  each  jaw.  Divided  into  pincers, 
middle  teeth  or  nippers,  intermediate  or  dividers,  and 
corners.  The  superior  surface  exhibits  the  external 
dental  cavity  which,  when  worn,  shows  the  central  and 
surrounding  enamels  ;  and  in  older  animals  the  dental 
star;  and  lattei)  the  >5Lternal  dental  cavity,  obliterated. 

Canines  or  tusks. — Two  in  number,  are  found,  in 
solipeds,  in  males  only :  they  seldom  are  shed,  and 
grow  but  once. 

Molars. — Twelve  on  each  jaw;  six  on  each  side. 
The  surface  of  these  teeth  is  inclined  from  inwards 
outwards  for  the  lower  jaw,  and  vice  versa  for  the 
upper  one.  They  present  the  aspect  of  a  grinding 
surface,  made  irregular  by  the  arrangement  and  pro- 
jection of  the  enamel.  The  first  three  molars  are 
caducous.         "s::^^^^^^^^^«2E^5^i<sd5!>»^^^^ 

Eye. — Organ  of  sight,  is  composed  of  accessory  and 
essential  organs.    c^4,^^i?g<I^ 


^ 


<^%,^a^t-*.-c  <r^  '^ 


c  -     J"  ^ 


o 


HEAD.  85 

Accessory  organ — orbital  cavity. — Formed  by 
the  orbital  process,  the  frontal,  laclirymal,  zygomatic 
bones,  and  part  of  the  zygomatic  process  of  the  tem- 
poral. It  is  closed  by  the  ocular  sheatli,  a  fibrous  en- 
velop attached  on  the  orbital  hiatus  and  forward  on 
the  internal  face  of  the  orbit,  and  surrounding  the 
seven  muscles  of  the  globe  of  the  eye. 

1.  Posterior  rectus  or  retractor-oculi  — Attach- 
ments: Rourid.tlie  optic  foramen,  external  face  of  the 
sclerotic.     Action  :  Pulls  the  globe  backwards. 

2.  Superior,  inferior,  external  and  internal  rec- 
ti.— Attachments:  In  the  bottom  of  the  ocular  sheath, 
and  external  surface  of  the  sclerotic.  Action  :  Turns 
the  pupillary  opening  upwards,  downwards,  outwards 
or  inwards. 

3.  Great  oblique  or  obliquus  superior  oculi. — 
Attachments  :  The  bottom  of  the  orlnt  and  the  ex- 
ternal surface  of  the  sclerotic.  Action  :  Pivots  the 
•eye  inwards  and  upwards. 

4.  Small  oblique  or  obliquus  jnferior  oculi. — 
Attachments  :  The  lacrymal  fossa  and  external  face  of 
the  sclerotic.  Action  :  Pivots  the  eye  outwards  and 
downwards. 

Eye-lids. — One  superior,  and  one  inferior.  They 
have  two  surfaces,  and  are  lined  internally  by  the  con- 
junctiva forming  the  conjunctival  sinus ;    they  have 


86  EQDINE  ANATOMY. 

two  borders  united  by  commissures  or  canthi,  the  free 
border  showing  the  openings 'of  the  Meibonian  glands. 
Structure :  1 — fibrous  plate  having  on  its  free  border 
2 — the  tarsus  ;  3 — muscles,  the  orbicularis-palpebrum 
and  orbito-palpebrum ;  4 — integuments  represented  by 
the  "skin  and  conjunctiva;  5. — ej^e-lashes;  6 — Mebo- 
nian  glands. 

Membrana  nictitans  or  third  eyelid,  or  winking 
EYELID. — A  fibro  cartilage  situated  at  the  inner  angle 
of  the  eye. 

Lachrymal  apparatus — lachrymal  gland. — Situ- 
ated on  the  superior  face  of  the  globe,  having  numerous 
ducts  called  hygrophthalmic  canals. 

Lachrymal  cardncula. — A  round  body  in  the  na- 
sal angle  of  the  eye. 

Puncta  lachrymalis. — Little  openings  on  each  eye- 
lid at  the  nasal  commissure. 

Lachrymal  ducts. — Continuation  of  the  puncta,  and 
emptying  in  the 

Lachrymal  sac. — Little  reservoir  lodged  in  the 
lachrymal  fossa  and  continuous  with  the  lachrymal 
duct ;  opening  at  the  lower  commissure  of  the  nostrils 
by  one  and  sometimes  two  orifices. 

Essential  organ — globe  or  the  eye. — Divided 
into  membranes  and  humours  or  media. 

Membranes — 1.  Sclerotic. — Two  faces,  the  external 


HEAD.  8T 

covered  by  the  muscles  and  adipose  tissue,  the  internal 
lined  by  the  clioroid.  The  anterior  0})ening  is  contin- 
uous with  the  cornea,  the  posterior  is  run  through  by 
the  optic  nerve.  Structure :  connective  tissue  mixed 
with  elastic  fibres  and  pigment. 

2.  Cornea. — Two  surfaces  and  a  circumference. 
Structure:  three  layers  ;  an  external,  the  conjunctival 
epithelium ;  a  middle,  composed  of  fasciculi  of  con- 
junctival fibrilla,  between  which  is  a  liquid  amorphous 
substance ;  and  an  internal,  portion  of  the  membrane 
of  the  aquous  humour. 

3.  Choroid. — Divided  by  the  ora  serrata  into  two 
zones,  one  posterior  or  choroid,  internally  in  contact 
with  the  retina  and  externally  with  the  sclerotic ;  one 
anterior  or  ciliary,  formed  by  ciliary  circle,  and  a  ciliary 
body,  from  which  hangs  the  ciliary  processes.  Structure  : 
four  layers ;  an  external,  composed  of  connective  and 
elastic  fibres  with  pigmentary  cells;  a  second  layer, 
vascular  and  nervous,  with  pigmentary  cells ;  a  third 
layer,  or  of  Ruysch,  formed  of  amorphous  substance ; 
and  an  internal  layer,  composed  of  hexagonal  cells 
containing  pigment. 

4.  Iris. — A  septum  in  front  of  the  crystalline  lens, 
with  the  pupil  in  its  centre,  through  which  appears 
the  "  soot-balls "  or  corpora  nigra,  portions  of  the 
uvea   which    covers    the   posterior   face    of    the   iris. 


88  EQUINE    ANATOMY. 

Structure :  a  proper  menbrane  with  unstriped  muscular 
fibres,  an  anterior  epithelial  layer,  and  a  posterior 
epithelial  or  uvea. 

5.  Retina. — An  expansion  of  the  optic  nerve.  Struc- 
ture :  connective  tissue  forming  the  external  and  inter- 
nal limitary  membrane  and  nerve  elements,  forming 
seven  layers  :  1 — one  of  rods  and  cones  ;  2 — external 
granular  ;  3 — intermediate  ;  4 — inner  granular ;  5 — 
molecular  ;  6 — ganglionic  ;  7 — of  fibres  of  optic 
nerves. 

Humours  or  media. — Crystalline  lens,  transparent 
lens,  enveloped  by  the  crystalline  capsula ;  vitrous 
humour  covered  by  the  hyaloid  membrane;  aquous 
humour  secreted  by  the  membrane  of  Descemet  or 
Demours. 

Ear. — Division :  External,  middle  and  internal 
ear. 

External. — Composed  of:  1 — external  auditory 
canal,  formed  by  the  petrous  portion  of  the  temporal 
bone;  2 — the  concha  or  pavillion  formed  by  the  con- 
chal,  annular  and  scutiform  cartilages,  and  moved  by 
ten  muscles :  1 — Zygomatico  auricularis.  Synonyms. 
Attolens  anterior,  (P).  Temporo- auricularis,  (L).  At- 
tachments :  Zygomatic  process  of  the  temporal  base  of 
the  concha  and  external  border  of  the  scutiform  carti- 
lage.    Action  :  Fulls  the  ear  forward.     2 — Temporo- 


HEAD.  89 

auricularis  externus  Synonyms.  Attoleris  maximus, 
.(P).  Attachments :  The  parietal  crest  and  the  inter- 
nal border  of  the  scutiform  and  conchal  cartilages. 
Action :  Adductor  of  the  concha.  3 — Scuto-auricu- 
laris  externus.  Sjmonyms.  Anterior  conchse,  (P). 
Attachments :  External  face  of  the  scutiform  and  the 
internal  side  of  tlie  concha.  Action:  E-otator  out- 
wards. 4 — Three  cervico-auricularis.  Synonyms.  Re- 
tralientesaurem,  (P).  Attachments  :  Tlie  cervical  liga- 
ment, the  superficial  to  tlie  posterior  face  of  the  con- 
cha, tlie  middle  on  the  outside  of  the  base,  and  the 
deep  at  the  base  of  the  conchal  cartilage.  Action : 
Pull  the  ear  backwards  and  in  rotation  outwards.  5 — 
Parotido  auricularis.  Synonyms.  Abducens  or  depri- 
mens  aurem,  (P).  Attachments :  The  parotid  gland 
and  at  the  base  of  the  concha.  Action:  abductor  of 
the  external  ear.  6 — Temporo-auricuhiris  internus. 
Synonyms.  Attolens  posterior,  (P).  Attachments; 
On  the  median  crest  origin  of  the  parietal  crest,  and 
on  the  internal  side  of  the  concha.  Action  :  Abductor 
•of  the  ear.  7 — Scuto-auricularis  internus.  Synonyms. 
Posterior  conchge,  (P).  Attachments  :  On  the  internal 
face  of  the  scutiform  and  at  the  base  of  the  concha. 
Action  :  Pivots  the  ear  outwards  and  backwards.  8 — 
Mastoido-auricularis.  Attachments  on  the  rim  of  the 
•external  auditory  hiatus  and  the  base  of  the  concha. 


90  EQUINE    ANATOMY. 

Action  :  Constricts  the  cartilaginous  tube  of  the  ear. 

Middle  ear  or  tympanum. — Division :  An  external 
wall  formed  by  the  membrana  tympani,  an  internal  with 
the  fenestra  ovale  separated  by  the  promontory  from 
the  fenestra  rotunda.  The  circumference  is  occupied 
by  the  mastoid  cells.  Internally  are  found  four  bones, 
the  malleus,  incus,  orbiculare  and  stapes ;  they  are 
moved  by  the  internal  muscle  of  the  malleus  and  the 
muscle  of  the  stapes  ;  this  cavity  is  lined  by  a  tine 
mucous  membrane  and  communicates  with  the  pharynx 
by  the  Eustachian  tube  or  guttural  ducts  of  the  tym- 
panum, a  long  canal  cleft  inferiorly,  through  which 
the  mucous  membrane  escapes  and  descends  to  form  the 
guttural  pouches. 

Internal  ear  or  labyrinth. — Division :  Osseous 
labyrinth ;  1 — a  vestibule  with  eight  orifices,  the  fen- 
estra ovale,  five  openings  of  the  semi-circular  canals, 
the  opening  of  the  seala  cochlea  and  the  forami- 
na for  the  branches  of  the  acoustic  nerve  ;  2 — the 
semi-circular  canals,  divided  into  superior,  posterior  and 
external.  3 — The  cochlea  or  snail  shell  twisted  round 
the  modiolus  and  divided  by  the  lamina  spiralis  into 
superior  and  inferior  scalse. 

Membranous  labyrinth. — 1.  Membranous  vetibule : 
formed  by  two  sacs,  the  superior  or  utriculus,  and  the 
inferior  or  sacculus ;  and  composed  of  two  layers,  the 


HEAD.  91 

external  cellular,  the  internal  epithelial.  2 — Mem- 
branous semi-circular  canals,  corresponding  to  the 
osseous  canals.  3 — Membranous  cochlea,  forming 
three  cavities:  one  inferior  tympanic,  one  superior  or 
vestibular,  one  middle  or  auditory,  containing  the  organ 
of  Gos^.  €  cn^ 

Fluids  of  labyrinth:  that  of  the  membranous  laby- 
rinth, or  endolymph ;  that  of  the  osseous  labyrinth, 
or  peri-lymph. 

Cranium* — Formed  by  the  frontal,  parietal,  occipi- 
tal, ethmoid,  sphenoid  and  temporal  bones.  Division  : 
Four  planes  and  two  extremities.  Superior  plane 
presents  the  internal  occipital  protuberance  with  its 
lateral  and  median  crests.  Inferior  plane,  the  basilar 
groove,  pituitary  fossa,  optic  fossa,  foramen  lacerum, 
cavernous  sinuses,  maxillary  fissures  and  mastoid  fossa. 
Lateral  planes  covered  with  digital  impressions.  Poste- 
rior extremity,  occiptal  foramen.  Anterior  extremity, 
the  crista-galli  process,  the  ethmoidal  fossa  and  the 
cribriform  plate  of  the  ethmoid. 

It  is  lined  by  three  meninges  :  The  external  or  dura 
MATER,  a  fibrous  membrane  forming  three  folds:  the 
falx  cerebri  between  the  cerebral  hemispheres,  which,  in 
old  animals,  has  as  its  posterior  extremity  the  Pacchi- 
onian glands  or  meningeal  granulations ;  the  tentorium 
cerebclli  between  the  cerebrum  and  cerebellum ;  the 


92  EQUINE    ANATOMY, 

suprasphenoid  or  pituitary  fold,  which  circumscribes- 
the  sella  turcica.  The  cranial  dura  mater  is  more  or 
less  adherent  to  the  bone,  and  is  lined  by  the  parietal 
layer  of  the  arachnoid  ;  it  gives  prolonged  sheaths  to 
the  nerves. 

The  middle  or  arachnoid  is  a  serous  membrane 
with  a  parietal  and  a  visceral  layer,  enclosing  a  cavity 
by  its  internal  face,  perforated  by  the  roots  of  the 
nerves  and  blood  vessels.  It  shows  iilaments  uniting 
it  to  the  pia  mater ;  passes  over  the  circumvolutions  of 
the  encephalon,  leaving  spaces  or  confluents  containing 
the  sub-arachnoid  fluid,  a  slightly  yellow  or  colorless 
but  limpid  and  transparent  liquid. 

The  internal  or  pia  mater,  a  cellulo-vascular  struc- 
ture, which,  by  its  external  face,  furnishes  the  neuril- 
emma of  the  nerves  and  filamentous  threads  to  the 
dura  mater.  From  its  internal  face  rise  blood  vessels 
dipping  into  the  nervous  substance. 

Encephalon. — Yolume,  closely  that  of  the  cranium. 
Weight,  about  twenty-two  or  twenty-three  ounces.  Di- 
vision :  Isthmus,  cerebrum  and  cerebellum.*^ yL^>v^ 

Isthmus. — a.  External  surface :  four  faces  and  two 
extremities.  Inferior  face  presents  annular  protuber- 
erance  or  pons  Varolii  or  mesocephalon,  crura-cerebri 
or  pedunculum  cerebri,  rachidian  bulb  or  medulla  ob- 
longata ;  superior  face  shows  the  upper  face  of  the 


HEAD.  93 

medulla  oblongata,  peduncnliim  cerebelli  or  crura  cere- 
belli,  valve  of  Yieussens,  corpora  quadrigemina  and  thai- 
ami  optici;  lateral  faces  present  the  proiile  of  the 
medulla  oblongata,  of  the  pons  Varolii,  of  the  pcdunc- 
ulum  cerebri  and  cerebelli,  of  the  corpora  quadrigemina 
and  thalami  optici ;  posterior  extremity  is  continuous 
with  the  spinal  marrow ;  anterior  extremity  passes  into 
the  corpora  striata. 

1.  Medulla  OBLONGATA. — Division:  Four  faces:  in- 
ferior shows  the  corpora  pyramidalia,  a  transverse  band, 
some  arciform  fibres,  the  corpus  olivare,  the  origin  of 
the  sixth  cranial  pair,  of  glosso  pharyngeal  and  of  the 
pneumogastric  ;  superior  face  is  covered  by  the  cerebel- 
lum, forms  the  floor  of  the  fourth  ventricle  and  shows 
the  calamus  scriptorius  and  the  corpora  restiforma; 
lateral  face  exhibits  the  profile  of  the  corpora  resti- 
forma and  corpora  pyramidalia. 

2.  Pons  Yarolii  with  its  two  borders  and  two  ex- 
tremities, which  form  the  middle  crura  cerebelli. 

3.  Crura  cerebri. — Separated  from  each  other  by 
the  interpeduncular  fissure  which  bifurcates  to  circum- 
scribe forward  the  mamillary  or  pisiform  tubercle,  lim- 
ited behind  by  the  pons  Yarolii,  in  front  by  the  optic 
nerves,  laterally  and  above  by  the  corpora  quadrigem- 
ina and  thalami  optici;  it  forms  laterally  the  band  of 
Keil  or  lateral  triangular  fasciculus. 


94  equine  anatomy. 

4.  Crura  cerebelli. 
die  is  the  largest;  the  posterior  tne  sii^aiiest  f  tney  cim^/ 

dh-ectly  into  the  cerebellum. ' ^  ^y^ZJi^^^^^^^^^f!^^ 

5.  Yalve  of  Vieussens. — Thin  lamella,  uniting  the  / 
two  anterior  cerebellar  peduncles. 

6.  Corpora  quadrigemina. — Anteriorly  the  tuber- 
cula  nates,  and  posteriorly  the  testes  uniting  outwardly 
to  the  corpus  geniculatum  externum. 

7.  Thalami  optici. — Inclined  inwardly  to  form  a 
deep  fissure  containing  the  anterior  peduncles  of  the 
pineal  gland  ;  this  fissure  presents  at  its  extremities 
the  anterior  and  posterior  common  openings ;  outward- 
ly shows  the  corpus  geniculatum  externum  and  inter- 
num ;  in  front  it  exhibits  the  semi-circular  band  or  taenia 
semi-circularis. 

8.  Pineal  gland  or  conarium. — Reddish-brown 
mass  resting  on  the  posterior  common  opening. 

9.  Pituitary  gland. — Synonyms.  Hypophysis  cer- 
ebri, supra  sphenoidal  appendage ;  fixed  to  the  inter- 
pedunculum  fissure  by  the  pituitary  stem  and  tuber- 
cinereum. 

(h.)  Internal  conformation. — Three  cavities.  1. — 
Middle  ventricle  of  the  thalami  optici.  Division  :  Two 
walls,  a  floor,  a  roof  with  the  anterior  and  posterior 
common  openings  separated  by  the  grey  commissure. 
The  posterior  extremity  is  continuous  with  the  aque- 


.       (P>/'^^  HEAD.  95 

duct  of  Sylvius  ;  the  anterior  presents  the  lamina  cine- 
rea  or  grey  root  of  the  optic  nerves ;  2 — Aqueduct  of 
Sylvius  posteriorly  opens  into  the  fourth  ventricle  ; 
3 — Posterior  cerebellar  or  fourth  ventricle  closed  su- 
periorly by  the  valve  of  Yieussens  and  of  Renault. 

{c.)  Stkucture  :  formed  of  three  fasciculi  of  white 
substance,  a  superior  or  corpora  restiforma,  an  inferior 
or  corpora  pyramidalia  and  a  lateral  or  intermediate; 
the  grey  substance  is  found  in  the  floor  of  the  fourth 
ventricle,  the  crura  cerebri,  the  lateral  or  intermediate 
fasciculi  of  the  bulb,  the  corpora  quadrigemina,  the 
thalami  optici  and  in  the  annular  protuberance. 

Cerebellum. — {a.)  External  surface  :  one  middle 
lobe  forming  the  anterior  and  posterior  vermiform 
processes ;  two  lateral  lobes,  beneath  which  the  cho- 
roid cerebellar  plexus  is  applied.  Its  external  surface 
is  covered  with  sulci ;  (Z>.)  Internal  surface  on  section 
shows  the  arbor  vitae  and  corpus  rhomboideum. 
Structure  :  the  white  substance  is  internal  and  ramify- 
ing, the  grey  substance  forms  cortical  layer. 

Cerebrum. — Division  :  Two  lateral  hemispheres. 
{a.)  External  surface  shows:  1 — Interlobularor  longitu- 
dial  fissure,  whicli  extends  down  to  the  corpus  callosum 
and  is  bound  posteriorly  by  the  fissure  of  Bichat,  and 
lodges  the  great  vena  Galeni  and  falx  cerebri ;  2 — ce- 
rebral hemispheres,  with  four  faces  covered  with  con- 


06  EQUINE    ANATOMY. 

volutions,  and  showing  the  mastoid  lobe,  the  fissure  of 
Sylvius  and  the  olfactory  or  ethmoidal  lobes  ;  an  ante 
rior  extremity  lodged  in  the  ethmoidal  fossa,  a  posterior 
resting  on  the  cerebellum. 

(h.)  Internal  surface.  1 — Corpus  callosum,  an  arch 
thrown  over  the  lateral  ventricles  uniting  the  two 
hemispheres,  and  offering  on  its  superior  face  the 
tractus  longitudinalis  ;  2 — lateral  or  cerebral  ventricles. 
Division :  An  anterior  and  a  posterior  or  reflexed  por- 
tion ;  they  are  separated  by  the  septum  lucidum,  a  thin 
median  lamella,  standing  vertically  between  them,  and 
by  the  fornix  or  trigonum  cerebralis,  which  serves  to 
support  the  septum.  On  the  floor  of  the  lateral  ven- 
tricles are  seen  from  forward  backwards ;  1 — the  cor- 
pora striata,  showing  inwardly  and  posteriorly  the 
taenia  semi-circularis  in  which  floats  the  choroid  plexus ; 
2 — the  hippocampi  or  cornu  Ammonis,  occupying  the 
floor  of  the  anterior  region  of  the  lateral  ventricle,  and 
is  prolonged  in  its  reflected  portion  and  having  their 
external  extremities  resting  on  the  mastoid  lobes ;  3 — 
the  velum  interpositum  or  choroid  plexus,  a  vascular 
expansion  of  the  pia  mater  penetrating  in  the  ventri- 
cles by  the  transverse  fissure.  A  fine  membrane,  the 
ventricular  arachnoid,  lines  the  cavity  of  the  ventricles ; 
it  secretes  a  liquid  analogous  to  the  cerebro-spinal  fluid. 
Structure :  the  grey  substance  forms  the  cortical  layer 


HEAD.  97 

of    the  cerebral  convolutions.     The  white  substance 

forms  in  the  hemisphere  the  centrum  ovale  of  Yieussens. 

Intermaxillary  space   or    throat.— Pharynx. — Its 

cavity  presents  seven  openings :  two  for  the  nasal  cav- 
ities ;  two  for  the  Eustachian  tubes  ;  one  for  the  larynx  ; 
one  for  the  oesophagus,  and  one  for  the  isthmus  of  the 
throat  or  of  the  fauces.  Structure  :  1 — a  mucous  mem- 
brane covered  bv  yellow  elastic  fibres ;  2 — seven  muscles : 
a.  palato  pharyni^eus  or  pharyngo-staphyleus  (described 
in  soft  palate)  'Jj^h.  Pterygo  pharyngeus  or  superior 
constrictor.  S^^^iiyins.  Pallito  pharyngeus.  At- 
tachments :  Pterygoid  process,  posterior  and  superior 
face  of  the  pharynx.  Action :  Perfect  constrictor  of 
the  pharynx  'A4c.  Hyo-pharyngeus  or  first  middle  con- 
strictorfcrZ.  Thyro-pharyngeus  or  second  middle  con- 
strictor iJe.  Crico-pharyngeus  or  inferior  constrictor. 
Attachments  ;  The  first  to  the  corner  of  the  os  hyoides, 
the  second  from  the  external  surface  of  the  thyroid 
cartilage,  the  third  from  the  cricoid  cartilage,  and  all 

three  endino;  on   the  median  fibrous   line    above   the 

*  I* 
pharynx,  are  all  constrictors  of  the  pharynx jU-y.  Ai'yte-^-^fcJt** 

no-pharyngeus.    Attachments  :  The  posterior  border  of 

the  arytenoid  to  the  origin  of  the  oesophagus  'Jfg.  Styio- 

pharyngeus.    Attachments  :  Inside  the  great  branch  of 

the  hyoid  bone  to  the  side  of  the  pharynx.     Action : 

Dilator.jro  3 — Blood  vessels,  the  pharyngeal  and  thyroid 


98  EQUINE    ANATOMY. 

arteries.  4 — Nerves :  glosso-pharyngeal,  pneumo-gas- 
tric,  great  sympathetic. 

Larynx* — Structure  :  five  cartilages.  1 — Cricoid, 
with  an  external  face,  presenting  two  conca^'e  articular 
f acettes,  and  an  internal  face  smooth ;  a  superior  and  in- 
ferior circumference ;  2 — Thyroid.  Division  :  A  body 
and  two  wings,  the  superior  border  of  which  presents 
a  mean  of  articulation  with  the  hyoid  and  a  notch  for 
the  superior  laryngeal  nerve ;  3 — Epiglottic,  with 
two  faces,  two  borders,  a  summit  and  a  base,  the  bor- 
ders having  prolongations  or  cartilages  of  Wrisberg 
extending  backwards ;  4 — Arytenoid,  two,  whose  exter- 
nal face  is  divided  by  a  ridge  in  two  portions ;  superior 
and  anterior  borders  unite  with  their  congeners ;  pos- 
terior border  projects  into  the  larynx ;  and  inferior 
gives  attachments  to  the  vocal  cord. 

Articulations. — 1 — the  thyroid  cartilage  to  the 
hyoid  bone,  by  the  extremities  of  the  cornua  and 
through  the  medium  of  the  thyro-hoid  membrane ; — 2 
the  thyroid  and  cricoid  cartilages  by  two  small  arthro- 
dia  and  the  crico-thyroid  membrane ;  3 — the  two  ary- 
tenoids by  their  superior  borders;  4 — the  arytenoid 
and  the  cricoid  cartilages  by  small  movable  arthrodia ; 
5 — arytenoid  to  the  thyroid  by  the  vocal  cords ;  6 — 
the  epiglottic  to  the  thyroid  cartilages  by  amphiar- 
throsis  ;  T — the  epiglottic  to  the    arytenoids   by  the 


HEAD.  99 

superior  vocal  cords  ;  8 — the  cricoid  cartilages  to  the 
tracliea  by  the  crico-tracheal  elastic  membrane. 

Muscles. — Three  extrinsic  :  1 — Sterno-thyroideus 
(see  inferior  cervical  region) ;  2 — Hyo-tliyroidens. 
Attachments  :  "Whole  extent  of  the  hyoid  cornu,  exter- 
nal face  of  the  thyroid  cartilages.  Action  :  Carries 
the  larynx  forward  and  upward  ;  3 — Hyo-epiglottideus. 
Attachments  :  Superior  face  of  the  body  of  the  hyoid 
bone,  and  antero-inferior  face  of  the  epiglottic  cartil- 
ages. Action  :  Pulls  the  epiglottic  cartilage  to  normal 
position.  Five  intrinsic  :  1. — Crico-thyroideus.  At- 
tachments :  from  the  cricoid  to  the  posterior  border  of 
the  thyroid,  it  shortens  the  larynx  ;  2. — Posterior  cri- 
co-arytenoideus.  Attacliments  :  bezel  of  the  cricoid, 
the  median  crest  and  the  posterior  tubercle  of  the  ary- 
tenoid, it  dilates  the  entrance  of  the  larynx ;  3 — 
Lateral  crico-arytenoideus.  Attachments  :  Side  of  the 
anterior  border  of  the  cricoid,  and  tubercle  of  the  ary- 
tenoid cartilage,  it  constricts  the  larynx ;  4 — Thyro- 
arytenoideus.  Attachments :  Internal  surface  of  the 
ala  of  the  thyroid  and  on  the  arytenoid  ;  it  is  a  con- 
strictor of  the  larynx;  5 — Arytenoideus.  Attachments  : 
Median  raphe  and  the  superior  part  of  the  external  face 
of  the  arytenoid  ;  it  constricts  the  larynx. 

Mucous  membrane  covered  with  stratified  tessalated 
epitelium  on  the  epiglottis  and  the  vocal  cords,  ciliated 


100  EQUINE    ANATOMY. 

elsewhere.  Blood  vessels :  laryngeal  arteries.  ]N^erves  : 
the  superior  and  inferior  laryngeal,  furnished  by  the 
pnenmo-gastric. 

The  external  surface  of  the  larynx  offers  four  planes  : 
a  superior,  inferior  and  two  laterals. 

The  internal  surface  offers  three  regions:  a  middle, 
the  glottis;  a  superior,  the  supra-glottis,  and  an  infe- 
rior, the  sub-glottis.  Tlie  first  is  comprised  between 
the  vocal  cords;  the  second  shows  the  two  ventricles 
of  tlie  larynx,  the  sub-epiglottic  sinus  and  the  entrance 
of  the  larynx ;  the  third  exhibits  the  posterior  border 
of  the  vocal  cords  and  the  sub-arytenoid  sinus. 

Salivary  glands.— 1.  Parotid.  Division:  Two  faces, 
two  borders  and  two  extremities.  External  face  shows 
a  longitudinal  groove  for  the  jugular  vein,  and  is  cov- 
ered by  the  parotido  auricularis  muscle.  Internal  face 
covers  the  guttural  pouch,  the  insertion  of  the  small 
oblique  muscle  of  the  head  and  mastoido  humeralis, 
occipito-hyoideus,  styloid  bone,  digastricus,  sterno-max- 
illaris,  maxillary  gland,  external  carotid  artery  and 
facial  nerve.  Anterior  border  rests  on  the  teraporo- 
maxlllary  joint,  subzygomatic  vessels  and  nerves  and 
maxillo-muscular  vessels.  Posterior  border  is  separated 
from  the  wing  of  the  atlas  by  the  levator  humeri. 
Superior  extremity  embraces  concha.  Inferior  extrem- 
ity is  comprised  in  the  angle  formed  by  the   jugular 


HEAD.  101 

and  glosso-facial  veins.  Blood  vessels  :  small  arteri- 
oles. I^erves :  facial,  inferior  maxillary  and  carotid 
plexuses. 

Duct  of  S tenon  lays  on  tendon  of  the  sterno-max- 
illaris,  enters  the  intermaxillary  space,  alongside  the 
internal  masseter,  above  the  glosso-facial  vein ;  reaches 
the  maxillary  lissure  ;  runs  up  in  front  of  the  anterior 
border  of  the  external  masseter,  obliquely  forward 
under  the  glosso-facial  vein  and  artery  ;  passes  through 
the  cheek  to  open  opposite  the  third  upper  molar. 

2.  Maxillary  or  sub-maxillary. — Division :  Two 
faces,  two  borders  and  two  extremities.  External  face 
corresponds  to  the  internal  pterygoideus,  the  digastri- 
cns,  the  sterno-m axillaris  and  the  cellulo  aponeurosis, 
which  separates  it  from  the  parotid.  Internal  face 
applied  to  the  side  of  the  larynx,  the  guttural  pouch, 
the  carotid  artery  and  nerves  accompanying  it.  Supe- 
rior border  margined  by  the  digastricus.  Inferior  bor- 
der is  in  contact  with  the  glosso-facial  vein.  Posterior 
extremity  rests  on  the  wing  of  the  atlas.  Anterior  ex- 
tremity is  between  the  pterygoideus  internus  and  the 
hyo-thyroideus  muscles.  Vessels :  innominate  branches. 
Is  erves  :  from  the  carotid  plexus. 

Duct  of  Wharton  runs  from  between  the  mylo-hyoid- 
eus  and  great  hyo-glossus,  crossing  outwards  the  glosso- 
facial  artery  and  great  hypo-glossal  nerve,  inwardly, 


102  EQUINE    ANATOMY. 

the  digastricus  and  the  lingual  nerve,  passes  between 
the  stjlo-glossus  and  the  sub  lingual  gland,  to  end  in 
front  of  the  frsenum  of  the  tono-ue. 

3.  Sublingual. — Division :  Two  faces,  two  borders, 
and  two  extremities.  External  face  covered  by  the 
mylo-hyoideus.  Internal  face  rests  on  the  duct  of 
Wharton,  the  stylo  and  genio-glossus  muscles.  Su- 
perior border  forms  the  lingual  crest.  Inferior  border 
lays  between  the  mylo-hyoideus  and  the  genio-glossus 
muscles.  Posterior  extremity  receives  the  lingual 
nerve.  Anterior  extremity  runs  to  the  angle  of  the 
inferior  maxillary  bone. 

Duct:8  of  Rivinus,  fifteen  or  twenty  open  on  the 

11" , ■    II     '_  -       -      Mil  -  II       —         I  — fr —    -'  -*- 

lingual  crest.  Blood  vessels,  sublingual  artery. 
^Nerves,  lingual  and  carotid  plexus. 

4.  Molar. — Superior,  along  the  superior  border; 
and  inferior  along  the  inferior  border  of  the  buccinator. 

5.  Labial,  lingual,  staphtline  or  palatine,  in  the 
lips,  tongue  and  velum  palati. 

AXGEIOLOGY. 

Arteries. — The  three  terminal  branches  of  the  prim- 
itive, or  common  carotid :  1 — occipital :  2 — internal ; 
■3 — external  carotid.    ■ 

a.  Occipital  artery  runs  under  the  transverse  pro- 
'Cess  of  the  atlas,  behind  the  guttural  pouch,  between 


HEAD. 


loa 


the  maxillary  gland  and  the  anterior  straight  muscle 
of  the  head,  reaches  the  anterior  foramen  of  the  atlas^ 
runs  through  it  into  the  fissure  of  the  external  surface 
and  terminates  by  the  occipito-muscular  and  cerebro- 
spinal arteries.     Its  collateral  branches  are  : 

1.  Prevertebkal. — Terminating  by  muscular  and 
meningeal  branches. 

2.  Mastoid. — Going  to  the  parieto-temporal  canal 
to  anastomose  with  the  spheno-spinal. 

3.  Atloido  muscular. — Running  backwards  and 
throus:h  the  atlas  to  anastomose  with  the  verte- 
bral. 

Terminal  branches :  Occipito  muscular. — Termin- 
ating by  asceTrdrng  and  descending  branches,  the  last 
anastomosing  with  the  superior  cervical. 

Cerebro-spinal. — Penetrates  the  antero-internal 
foramen  of  the  atlas,  enters  the  vertebral  canal,  and 
terminates  by  two  branches — one  forming  the  basilar 
trunk,  the  other  the  median  spinal. 

Basilar  trunk. — Situated  on  the  inferior  face  of 
the  bulb  and  pons  Varolii,  and  dividing  into  two 
branches  wliich  give  off  the  posterior  cerebral  artery. 
It  sends  collateral  branches  to  the  bulb  and  pons  Var- 
olii, the  posterior  arr^s4l^r"Ki^  Ts^'efegllar  arteries  and 
two^lwasciie^-tothe-mt^'ntrl  cai*odT4-. 

PosTERioRs^ERKBR54*   tBr»inate"Tit€  'Bltsiiar^'btfmfev 


104  EQUINE    ANATOMY. 

Tli^are  given  off  behind  the  maxilla^r  tub^cle  ^an-d 
receive  the  posterior  communicating  arterjN 

Median  spinal  follows  the  spinal  marrow,  back- 
wards to  its  end,  being  supplied  by  branches  from  the 
vertebral,  intercostal,  lumbar  and  lateral  sacral. 

h.  Internal  carotid. — Ascends  beneath  the  cra- 
nium to  the  foramen  lacerum,  reaching  through  the 
carotid  fossa  of  the  external  surface  of  the  sphenoid, 
the  carotid  notch  of  the  superior  border,  and  then 
into  the  cranium  by  a  double  flexure,  terminates  by 
^ke^pofete^r  eom-miitTTcatittg  artery,  which  ana.yl;omQac.* 
-wrri^  the  posterior  cerebral,  and  by  a&ot-her  branoh 
which  furnichca  the  middle  and  anterior  cerebral. 

c.  External  carotid. — Continuation  of  the  prim- 
itive carotid,  runs  forward  to  the  posterior  border 
of  the  long  branch  of  the  hyoid  bone,  passes  between 
it  and  the  stylo-hyoideus,  bends  upward,  and  near  the 
neck  of  the  maxillary  bone  divides  into  its  terminal 
branches — the  superficial  temporal  and  internal  maxil- 
larj.  Its  collateral  branches  are  the  glosso-facial,  the 
maxillo-muscular  and  posterior  auricular. 

1.  Glosso- facial. — Rises  from  the  external  carotid 
as  it  passes  beneath  the  stylo-hyoideus,  turns  down- 
wards on  the  side  of  the  pharynx  in  the  intermaxillary 
space,  enters  the  maxillary  groove,  becomes  superficial 
on  the  anterior  border  of  the  masseter  muscle,  to  the 


HEAD.  105 

lateral  surface  of  the  face,  and  divides  into  ascending 
and  descending  branches  ramifying  in  the  muscles  of 
that  region.  Its  collateral  branches  are  :  1 — Pharyn- 
geal, terminating  in  the  velum  palati  and  the  walls  of 
the  pharynx;  2 — Lingual,  goes  to  the  tongue  in  its 
upper  portion,  anastomosing  in  front  with  that  of  the 
opposite  side,  forming  a  large  arch ;  3 — Sublingual, 
supplies  lower  part  of  the  tongue  and  the  buccal  mu- 
cous membrane;  4 — Inferior  coronary,  supplies  the 
lower  lip  and  muscles  of  the  inferior  part  of  the  lat- 
eral surface  of  the  face ;  5 — Superior  coronary,  goes 
to  the  upper  lip,  where  it  anastomoses  with  the 
palate. 

2.  Maxillo-muscular. — Passes  between  the  parotid 
gland  and  the  posterior  labial  border  of  the  maxillary 
bone,  where  it  divides  into  an  external  superficial  and 
an  internal  deep,  branches  going  to  the  masseter 
muscles. 

3.  Posterior  auricular. — Passes  upwards  under  the 
parotid  to  the  base  of  the  concha,  passing  on  its  pos- 
terior face  to  the  superior  extremity,  sending  off  a  few 
glandular  and  muscular  branches.  , 

Superficial  temporal — Pas^'''*trp^rds'  between 
the  parotid,  guttural  pouch  and  the  condyle  of  the  max- 
illary bone,  to  terminate  in  the  anterior  auricular  ancj 
8ub-zygomatic  trunk. 


106  EQUINE    ANATOMY. 

Anterior  auricular. — -liunning  behind  the  temporo- 
maxillary  joint  beneath  the  parotid,  to  reach  the  cro- 
taphite  muscle,  and  after  giving  glandular,  auricu- 
lar and  mus(;ulai:  branches  tern>inate&r/; — J        ^ 

SuB-zYGOMATic. — 1  asscs  outwards  between  the  an- 
terior border  of  the  parotid  and  the  posterior  border 
of  the  maxillary  bone  with  the  facial  nerve,  and  divides 
into  the  transversal  artery  of  the  face,  which  rims  hor- 
izontally on  the  superior  border  of  the  external  masse- 
ter  and  ramifies  in  it,  and  into  the  masseteric,  going  to 
the  same  muscle.         ,         •  _  ,    >^  -^^  fe,   , ,  ^uoAAytUy 

Internal  maxillary. — Running  to  tlie  subsphenoi- 
dal  canal,  it  passes  through  to  the  orbital  hiatus  and 
arriving  at  the  maxillary  opening  dips  into  the  pala- 
tine canal  as  the  palato-labial.  Collateral  branches : 
1 — inferior  dental,  traverses  the  inferior  maxillo 
dental  canal  to  end  at  the  mental  foramen  in  two  small 
twigs,  one  external  anastomosing  with  the  inferior 
coronary,  one  deep  to  the  roots  of  the  incisive  teeth 
and  tusk.  It  sends  collateral  branches  to  the  molar 
teeth  and  muscles  of  the  masseteric  regions ;  2 — ptery- 
goid, going  to  the  pterygoid  and  peristaphileus  muBcles ; 

3 tympanic,  'to  the  tympanum  with  branches  to  the 

guttural  pouches;  4 — spheno-spinal,  enters  the  temporo- 
parietal canal  to  anastomose  with  the  mastoid  artery 
/C^lLdlSp^  the  occipital ;    5 — posterior  deep  temporal,  to  the 


HEAD. 


107 


crotapliite  muscle  in  the  temporal  fossa ;  6 — anterior 
deep  temporal,  in  the  crotaphite  also,  and  the  adipose 
tissue  of  the  fossa;  7 — ophthalmic,  from  the  ocular 
sheath,  return  into  the  cranium  through  the  orbital 
foramen,  and  divides  into  meningeal  and  nasal  branches. 
The  orbital  portion  gives  off  muscular  branches,  cen- 
tral artery  of  the„  reiinat  ciliary,  supra  orbital  and 
lachrymal ;  the  cranial  portion,  the  cerebral  branches ; 
8 — buccal,  supplies  the  molar  glands,  the  buccinator 
and  the  maxillo-labialis  rnuscles;  9 — staphyline,  to  the 
velum  palati ;  10 — superior  dental,  goes  to  the  supe- 
rior raaxillo-dental  canal,  and  distributed  like  the  infe- 
rior dental;  11 — nasal,  runs  through  the  nasal  foramen 
into  the  nasal  fossa,  where  it  ends  by  external  and 
internal  branches,  ^j  ^       '  "    '^z; 

Palato-labial,  passesrrom  the  inaxfflai^  hiatus  to  ^ 
tlie  palatine  canal,  through  it  to  the  front  part  of  the 
palate,  to  the  incisive  foramen  where  it  anastamoses 
with  the  opposite  one,  forming  a  single  trunk,  which, 
passing  through  the  incisive  foramen,  reaches  the  upper 
lip  and  terminates  by  anastamoses  witli  the  superior 
coronary. 

Veins. — Three  principal  trunks :  superficial  temporal, 
internal  maxillary  and  sinuses  of  the  encephalic  dura 
mater ;  they  form  the  root  of  the  jugular. 

1.  Superficial  temporal. —  Satellite  of  the  temporal 


108  EQUINE    ANATOMY, 

arterial  trank   with  two  principal   roots,  the   anterior 
auricular  and  the  sub -zygomatic. 

2.  Internal  maxillary. — Supplied  by  the  buccal 
vein.  It  receives  numerous  collateral  branches,  viz  : 
the  lingual,  inferior  dental,  a  deep  temporal  trunk  and 
a  pterygoid. 

3.  Cephalic  sinuses  of  the  dura  mater. — Four 
principal :  the  sinuses  of  the  falx  cerebri,  the  cavern- 
ous or  sphenoidal,  the  occipito-atloid  and  the  rudiment- 
ary sinuses,  divided  into  lateral  and  inferior  median. 
These  sinuses  are  supplied  from  the  dura  mater  or  from 
nervous  substance  ;  some  of  the  last  are  superficial, 
the  others,  internal,  are  provided  by  the  great  vein  of 
the  brain  or  vena  G-aleni.  All  the  sinuses  collect  through 
the  means  of  the  parieto-temporal  and  subsphenoidal 
confluents,  and  empty  into  the  temporal,  pterygoid  and 
occipital  veins. 

Other  veins  of  the  head  considered  as  affluents  of 
the  jugular,  are  :  1 — the  maxillo-muscular  ;  2 — the 
posterior  auricular  ;  3 — the  occipital ;  4 — the  external 
maxillary  or  glosso-facial,  formed  by  the  angular  of 
the  eye  and  another  small  branch,  by  the  alveolar, 
labial  or  coronary,  buccal  and  sublingual  as  collateral 
branches. 

LymphaticSi— Two  groups:  1 — The  pharyngeal,  sit- 
uated on  the  lateral  sides  of  the  pharynx  below  the 


HEAD.  109 

guttural  poncli,  and  receiving  all  the  lympliatics  of  the 
head  ;  2 — Tlie  submaxillary,  situated  in  the  intermax- 
illary space,  and  receiving  the  lymphatics  of  the  tongue, 
cheeks,  lips,  nostrils  and  nasal  fossae. 

IVEUROLOGY. 

Twelve  pair  of  cranial  nerves. 

1.  Olfactory. — Formed  by  the  olfactory  lobe, 
which  has  the  appearance  of  a  ganglion,  grey  inferiorly, 
and  white  superiorly.  It  rises  by  two  roots  of  white 
substance,  which  unites  into  one  band,  and  is  situated 
in  the  ethmoidal  fossa,  where  through  the  foramina  of 
the  cribriform  plate  of  the  ethmoid,  it  sends  the  true 
nerves.  The  olfactory  lobes  are  hollowed,  and  com- 
municate with  the  cavity  of  the  lateral  ventricules. 
The  nerves,  varying  in  number,  ramify  in  the  mu- 
cous membrane  of  the  septum  nasi  and  ethmoidal  vol- 
utes. They  are  the  special  nerves  of  the  organs  of 
smell. 

2.  Optic. — E.ise  on  the  external  side  of  tlie  thalami 
optici  by  white  bands,  and  from  the  corpora  quadri- 
gemina.  Course :  Pass  in  front  of  the  cerebral  pedun- 
cles, arrive  at  the  inferior  face  of  the  brain,  form  the 
chiasma,  reach  the  optic  duct,  and  perforate  the  ocular 
envelope  at  the  bottom  of  the  ocular  globe,  and  enter 


110  EQUINE    ANATOMY. 

the  eye  as  the  retina.     They  are  exclusive  to  the  sense 
of  sight.  ,    ^ 

3.  Common  oculo  motor. — Emanates  from  the  cere- 
bral peduncles  near  the  peduncular  fissure  by  eight 
branches.  Course  :  The  single  trunk  of  the  nerve  runs 
outwards  to  the  smallest  supra  sphenoidal  canal,  passes 
through  the  orbital  liiatus,  and  ramifies  in  the  muscles 
of  the  eye,  except  the  external  and  posterior  recti  and 
the  great  obliqiie.     Functions  :  Essentially  motor. 

4.  Fathetic^rinternal  oculo  motor. — Kises  from 
the  band  of  E,eil  behind  the  corpora  quadrigemina  by 
two  roots.  Its  course  is  outwards,  downwards  and  for- 
wards to  reach  the  smallest  of  the  susphenoidal  canak, 
penetrate  the-  outer  sheath  and  ramify  in  the  great 
oblique  muscle  of  the  eye.     Functions  :  Motor. 

5.  Trigemini  or  trifacial. — Is  a  mixed  nerve,  hav- 
ing an  external  root,  sensitive,  and  an  internal,  motor. 

Sensitive  root. — The  largest  comes  from  the  an- 
nular protuberance ;  it  runs  forward  and  downwards 
to  the  occipito-spheno-temporal  hiatus,  and  terminates 
in  the  Gasserian  ganglion.  This  ganglion  is  crescent 
shape,  and  situated  in  the  cartilaginous  substance 
which  closes  the  foramen  lacerum ;  it  gives  origin  to 
two  branches,  one  passes  out  of  the  cranium,  the  other 
is  lodged  in  the  external  fissure  of  the  cranial  face  of 
the  sphenoid  and  bifurcates;  thus  at  its  origin  is  divided 


HEAD.  Ill 

into  three  branches,  the  ophthahnic  and  superior  naaxil- 
lary  nerves,  the  inferior  maxillary  nerve. 

Motor  root. — Runs  forward  from  the  pons  Yarolii 
under  the  inferior  face  of  the  ganglion  of  Gasser,  and 
soon  mingles  with  the  inferior  maxillary  branch  of  the 
sensitive  root. 

a.  Ophthalmic. — Course :  Enters  the  susphenoidal 
canal  with  the  third  and  fourth  pairs,  and  in  it  divides 
into  the  frontal,  lachrymal  and  nasal  or  palpebro-nasal 
nerves ;  the  frontal  going  to  the  orbital  foramen,  the 
lachrymal  ramifying  in  tlie  lachrymal  ghmd,  the  nasal 
reenters  the  cranium  with  the  ophthalmic  artery,  runs 
through  the  plate  of  the  ethmoid  into  the  nasal  fossa, 
where  it  divides. 

h.  Superior  maxillary. — Origin :  Internal  and  su- 
perior portion  of  the  Gasserian  ganglion.  Course  : 
Placed  in  a  groove  on  the  internal  face  of  the  sphe- 
noid, soon  reaches  the  largest  sphenoidal  canal,  runs 
to  the  orbital  hiatus,  passes  through  the  supra-maxillo- 
dental  canal,  where  it  dips  and  runs  as  far  as  the  lateral 
surface  of  the  face,  where  it  terminates  by  suborbital 
branches.  Collateral  branches :  The  orbital  to  some 
muscles  of  the  eye ;  the  great  or  anterior  palatine  to 
the  palatine  groove  and  to  the  palate ;  the  staphyline 
or  posterior  palatine  to  the  velum  palati ;  the  nasal  or 
spheno-palatine  to  the  pituitary  membrane;  the  dental 


112  EQUINE    ANATOMY. 

to  the  teeth  of  the  superior  jaw.  Termmal  branches  : 
The  suborbital  to  the  skin  and  muscles  of  the  nostrils 
and  upper  lip. 

c.  Inferior  maxillary. — Course :  leaving  the  cra- 
nium, it  passes  inside  the  temporo-maxillary  joint,  runs 
forwards  and  downwards  towards  the  maxillo-dental 
canal,  through  which  it  passes  and  comes  out  at  the 
mental  foramen  and  terminates  in  the  mental  nerves. 
Collateral  branches :  1 — the  masseterine,  to  the  mas- 
seter  muscle  after  giving  off  the  posterior  deep  and 
middle  deep  temporal ;  2 — the  buccal,  for  the  lateral 
face  of  the  cheek  after  furnisliing  the  anterior  deep 
temporal ;  3 — the  nerve  of  the  internal  pterygoid 
muscle  ;  4 — the  superficial  temporal  or  sub-zjgomatic, 
which  anastamoses  with  the  facial ;  5 — the  lingual,  to 
the  tongue ;  6 — the  nerve  of  the  mylo-hyoideus  mus- 
cle ;  7 — dental  branches  to  the  teeth  of  the  inferior 
jaw.  Terminal  branches  to  the  inferior  lip  united 
with  a  branch  of  the  facial  nerve. 

6.  External  oculo-motor. — Origin :  on  the  rachi- 
dian  bulb  behind  the  annular  protuberance.  Course  : 
runs  through  the  sphenoidal  canal  to  the  orbit,  ramify- 
ing in  the  external  rectus  of  the  eye. 

7.  Facial. — Motor  at  its  origin,  it  becomes  mixed 
afterwards.  Origin :  from  the  bulb  immediately  be- 
hind the  pons  Varolii.     Course :  outwards,  takes  the 


HEAD.  113 

iaternal  auditory  hiatus  to  the  aqueduct  of  Fallopius, 
through  the  stjlo-mastoid  foramen,  then  under  the 
parotid,  to  the  posterior  border  of  the  maxillary  bone, 
on  the  external  face  of  the  masseter  and  terminates  by 
the  zygomatic  plexus.  Collateral  branches :  1  and 
2 — the  great  and  small  superficial  petrosal  nerve  ;  3 — 
the  nerve  of  the  muscle  of  the  stirrup  ;  4: — the  nerve 
of  the  corda  tympanii,  all  to  the  internal  ear ;  5 — an 
anastomotic  branch  to  the  pneumogastric ;  6 — the 
nerve  of  the  stylo-hyoideus  muscle ;  7 — of  the  digas- 
tricus ;  8 — of  the  great  kerato-hyoideus  ;  9 — a  cervical 
branch ;  10 — nerves  to  the  guttural  pouches  and  to 
the  parotid  gland ;  11 — the  three  auricular  nerves, 
posterior,  middle  and  anterior.  Terminal  branches 
form  the  sub-zygomatic  plexus,  over  the  external  sur- 
face of  the  masseter  muscle  and  ramifying  in  the  tissue 
of  the  cheeks,  lips  and  nostrils. 

8.  Auditory  or  acoustic. — Origin :  From  the  bulb 
by  two  branches,  one  from  the  restiform  bodies,  the 
other  from  the  floor  of  the  fourth  ventricle.  Course  : 
Passes  behind  the  seventh  into  the  internal  auditory 
hiatus,  and  divide  in  two  branches,  anterior  and  pos- 
terior, ramifying  into  the  cochlea,  the  vestibulum  and 
semicircular  canals. 

9.  Glosso  pharyngeal. — Origin:  On  the  side  of 
the  bulb  between  tlie  restiform  bodies  and  the  lateral 


114  EQUINE  ANATOMY. 

fasciculus  of  the  bulb,  by  eight  or  ten  roots,  uniting  to 
forjn  the  petrous  ganglion.  Course :  Downwards  with 
a  curve  concave  forward,  behind  the  great  branch  of 
the  hyoid  bone,  between  the  guttural  pouches  and  mas- 
seter  muscle,  runs  alongside  the  hyoid  bone  and  reaches 
the  base  of  the  tongue,  where  it  terminates.  Collateral 
branches :  1 — The  nerve  of  Jacobson,  giving  off  the 
great  and  small  deep  petrosal ;  2 — Branches  to  the 
superior  cervical  ganglion  ;  3 — Branch  to  the  cartiod 
plexus  ;  4 — a  pharyngeal  nerve  to  the  superior  wall 
of  the  pharynx. 

10. — Fneumogastric  or  par  vagum. — Origin:  Two 
roots:  the  sensitive  from  the  grey  mass  near  the  floor 
of  the  fourth  ventricle  behind  the  glosso-pharyngeal, 
then  passes  out  of  the  cranium  to  the  jugular  ganglion  ; 
the  motor  root  rises  more  posteriorly  from  the  middle 
of  the  respiratory  track,  runs  also  outwards  and  goes 
to  the  jugular  ganglion,  which  is  elongated,  flattened 
from  above  below  and  imbedded  in  the  cartilaginous 
mass  closing  the  foramen  lacerum.  Course  :  After  its 
■connection  with  the  ganglion,  the  mass  is  united  to  the 
spinal,  but  soon  separates  from  it,  leaves  the  glosso- 
pharyngeal pass  between  them  alongside  and  behind 
the  guttural  pouches,  crosses  the  occipital  artery,  unites 
with  the  cervical  portion  of  tlie  great  sympathetic, 
passes  into  tlie  tliorax,  and  then  separates  from  this 


HEAD.  115- 

last  nerve.  In  the  chest  the  right  nerve  turns  obliquely 
round  the  axillary  artery  to  place  itself  outside  the 
trachea  until  the  root  of  the  bronchia,  where  it  ends ; 
the  left  nerve  remains  attached  to  the  artery,  crosses 
outv^ards  the  origin  of  the  aorta,  and  terminates  by 
branches  which  give  rise  to  the  bronchial  plexus  and 
oesophageal  nerves.  Collateral  branches :  1 — Branches 
to  the  superior  cervical  ganglion ;  2 — The  pharyngeal 
to  the  superior  face  of  the  pharynx;  3 — The  superior 
laryngeal  to  the  susglottic  portion  of  the  larynx  ;  4 — 
Branches  to  inferior  cervical  ganglion ;  5 — Inferior 
laryngeal  or  recurrent  nerves,  which  rise  from  the  tenth 
into  the  thoracic  cavity,  and  run  forwards  and  upwards 
into  the  larynx,  where  they  divide  into  the  muscles  and 
mucous  membrane  of  the  subglottic  portion.  Terminal 
branches  :  Bronchial  plexus  going  to  the  mucous  mem- 
brane of  the  bronchia ;  oesophageal,  divided  into  supe- 
rior and  inferior,  the  last  terminating  in  the  walls  of 
the  stomach  ;  the  former  into  the  left  sac  of  that  organ, 
and  the  solar  plexus. 

II.  Spinal  OR  ACCESsoRius. — Origin:  from  the  cer- 
vical marrow,  runs  upwards  and  forwards  in  the  verte- 
bral canal  till  it  reaches  the  tenth  pair,  with  which  it 
comes  out  of  the  cranium.  Course :  first  united  to 
the  par  vagum,  it  soon  leaves  it,  runs  backwards,  passes 
under  the  maxillary   gland,  arrives   at  the  posterior 


116  EQUINE    ANATOMY. 

border  of  the  levator  humeri ;  downwards  to  the  front 
of  the  shoulder,  then  turns  upwards  under  the  cervical 
trapezium  muscle  and  terminates  in  the  dorsal  portion 
of  the  same;  while  it  gives  several  muscular  branches, 
it  receives  some  from  the  first,  second,  tliird,  fourth 
and  fifth,  and  sometimes  sixth,  cervical  pairs. 

12.  Gkeat  hypoglossus. — Origin:  from  the  inferior 
face  of  the  bulb,  by  twelve  roots,  which  run  through 
the  dura  mater  by  two  or  three  fasciculi  and  then 
unite  into  one  trunk.  Course :  after  first  communi- 
cating with  the  first  cervical  pair,  it  passes  between  the 
tenth  and  eleventh  cranial  pairs,  runs  downwards 
alongside  the  guttural  pouches,  communicates  with 
the  superior  cervical  ganglion,  goes  outside  the  exter- 
nal carotid  on  the  side  of  the  pharynx  and  larynx,  dips 
between  the  mylo-hyoideus  and  basio-glossus  and  ter- 
minates in  the  tongue. 

Sympathetic  IVerve— Cephalic  portion  is  composed 
of  three  ganglions :  the  ophtlialmic,  resting  on  the 
common  oculo-motor  nerve,  is  very  small ;  the  spheno- 
palatine or  ganglion  of  Meckel,  varying  in  disposition, 
generally  found  under  the  superior  maxillary  nerve,  it 
is  the  largest  of  the  three  ;  the  otic  or  ganglion  of 
Arnold,  not  always  present ;  when  it  exists,  it  is  inside 
the  origin  of  tlie  inferior  maxillary  nerve. 


CHAPTER  V. 


T  RU  isr  K. 

Supporting  the  head  at  the  anterior  extremity  and 
terminating  posteriorly  by  the  tall ;  it  has  for  base,  od 
the  median  line  a  series  of  bones  called  vertebrae,  and 
is  composed  of  three  cavities;  the  thoracic;  the  ab- 
dondnalj  separated  by  the  diaphragm  muscle ;  and  the 
pelvic  cavity,  a  dependance  of  the  abdominal. 

Vertebrie — General  characters. — They  are  single 
bones  perforated  by  the  vertebral  foramen,  which  in  the 
series  forms  the  vertebral  canal.  Division  :  A  body 
and  annular  portion.  TJie  body  has  two  faces :  one 
superior  with  two  triangular  surfaces  and  two  grooves« 
for  venous  sinuses ;  the  inferior  with  a  crest  sometimes 
called  the  inferior  spinous  process.  It  has  two  ex- 
tremities :  an  anterior  with  a  round  head  more  or  less 
prominent,  one  posterior  with  a  cavity  for  the  reception* 
of  the  head.  The  antudaafcportion  has  an  internal 
surface,  concave  and  forrifetg  the  vertebral  foramen  '; 


118  EQUINE    ANATOMY. 

and  ail  external,  presenting  the  superior  spinous  pro- 
cess and  two  transverse  processes.  In  front  and  be- 
hind are  found  two  articular  facets,  and  at  their  base 
notches  for  the  formation  of  the  foramina  of  conjuga- 
tion. Development :  two  principal  and  five  secondary 
centers. 

In  the  vertebral  canal  is  found  the  spinal  makkow. 
It  is  covered  by  the  three  membranous  envelopes,  dura 
mater,  arachnoid  and  pia  mater.     It  is  a  thick,  white, 
hollow  mass,  continuation  of  the  medulla  oblongata, 
and  ending  in  a  point  at  the  anterior  third  of  the  sacral 
canal.     Weighing  about  ten  ounces,  it  is  slightly  de- 
pressed from  above  below,  and  presents  a  brachial  and 
lumbar  enlargements  or  bulbs  where  the  nerves  of  the 
fore  and  hind  extremities  are  given  off.     Its  external 
surface  shows  on  the  superior  and  inferior  face  a  deep 
fissure,  and  on  each  side  of  these,  two   others  scarcely 
noticeable.     Its  internal  structure  shows  that  it  is  hol- 
low, and  presents  in  its  middle  a  mass  of  grey  matter 
surrounded  by  white  substance.    They  are  so  arranged 
that  the  superior  and  inferior  fissures  of  the  external 
surface  are  separated  by  a  white  and  a  grey  commis- 
sure, the  last  tending  upwards  and  downwards  towards 
the  surfaces  of  the  organ  prolongations  or  cornua.  The 
medulla  receives  blood  from  arteries  of  the  pia  mater, 
and  branches  of  the  median  spinal  artery. 


CHAPTER  YL 


IS^  E  C  K  . 


OSTEOLOGY. 

Seven  cervical  vertebrae. 

General  characters:  They  are  the  longest  and  thick- 
est of  all ;  the  inferior  spinous  process  of  the  body  is 
well  developed ;  the  head  well  detached  ;  the  cavity 
very  deep  and  larger  than  the  head  it  receives  ;  the 
superior  spinous  process  is  a  rough  crest ;  the  trans- 
verse processes  are  very  large,  bending  downwards  and 
perforated  at  their  base  by  the  trachelian  foramen  ; 
the  articular  facets  are  plano-convex  and  very  wide  ; 
the  foramen  of  conjugation  very  large. 

Specific  characters  :  Firsts  or  atlas  is  very  large  and 
more  flat ;  the  body  is  quite  small ;  its  inferior  spinous 
process  is  replaced  by  a  tubercle ;  its  superior  face  is 
divided  into  a  surface  for  ligamentous  attachment,  and 
an  articular  surface ;  it  has  no  head  nor  cavity  behind  ; 
in  their  stead  are  found  forward  two  deep  cavities 
formed  by  four  concave   facets  for   articulation   with 


120  EQUINE    ANATOMY. 

tlie  occipital ;  beliind  are  two  piano  convex  facets  for 
articulation  with  the  axis ;  it  has  no  superior  spinous 
process,  but  a  rough  surface ;  its  transverse  processes 
are  very  wide  and  have  three  foramina.  Development : 
six  nuclei  of  ossification. 

Second^  or  axis. — The  longest  of  all ;  has  no  head  but 
the  odontoid  process  ;  the  inferior  spinous  process  is 
fiharp  ;  the  superior  thick  and  bifid  behind  ;  the  trans- 
verse process  is  sharp  and  has  a  single  tubercle ;  it 
iias  no  articular  facets  forward,  and  shows  a  deep 
notch  sometimes  a  foramen  in  front  of  the  body. 

Third.  The  space  between  the  anterior  and  posterior 
articular  processes  is  deep. 

Fourth.  These  are  then  united  by  a  thin  edge. 

Fifth.  There  by  a  rough,  thick  crest.  In  all  three 
the  transverse  processes  are  bitubercular. 

Sixth.  Transverse  processes  tritubercular. 

Seventh,  or  prominent  has  a  superior  spinous  process 
VQvy  high,  no  inferior  one,  a  concave  facet  on  the 
border  of  tlie  posterior  cavity  ;  the  transverse  processes 
are  unitubercular  ;  no  trachelian  foramen  ;  the  vertebral 
canal  is  very  large. 

SYIVDESMOLOGY. 

General  articulations. — That  of  body  :  Amphiar- 
thosis.     Articular  surfaces :  Head  and  cavity  of   the 


NECK.  121 

body.  Means  of  union  :  Fibro-cartilnge  and  a  supe- 
rior and  inferior  common  v^ertebral  liii'Mment. 

That  of  tlie  annular  part :  Double  artlirodia.  Artic- 
ular surfaces  :  Articular  facets.  Means  of  union  :  Inter- 
spinal ligament,  inter  annular  ligament,  two  capsular, 
superior  spinal  ligament  (cervical  portion)  or  ligamen- 
tum  nuclise,  composed  of  a  funicular  cord  and  two 
median  sheets  of  yellow  elastic  tissue.  Motion  :  Sliding. 

Special  articulations — Atloido-occipital :  Condy- 
loid. Articular  surfaces :  Two  condyles  of  tlie  occipi- 
tal, two  cavities  in  front  of  the  atlas.  Ligaments  :  One 
capsular  with  four  reinforcing  bands.  Two  synovial  cap- 
sulse,  one  for  each  condyle  and  cavity.  Motion  :  Flex- 
ion, extension,  lateral  inclination  and  circumduction. 

AxoiDO-ATLOiD. — Troclioid  or  lateral  ginglymus.  Ar- 
ticular surfaces :  A  groove  on  tlie  superior  face  of  the 
body  of  tlie  atlas,  and  two  facets  on  each  side  of  it,  the 
inferior  face  of  the  odontoid  process  of  the  axis  and  the 
two  facets  laterally.  Ligaments  :  Superior  and  inferior 
atloido-axoid  ligaments,  odontoid  ligament,  one  capsu- 
lar.    One  synovial  capsnla.     Motion:  Rotation. 

MYOLOGY. 

Superior  region  :  Seventeen  muscles. 
1.  Cervical   trapezium. — (See    dorsal   region,    de- 
scribed as  cervical  portion  of  t^e  trapezium.) 


/^tUU^. 


v^ 


122  EQUINE    ANATOMY. 

2.  IIhom:boideus. — Synonyms.  Kliomboidens  longns 
and  brevis,  (P).  Ccrvico-subscapularis,  (G).  Dorso- 
scapularis,  (L).  Attachments  :  The  funicular  portion 
of  the  cervical  ligament,  tlie  apex  of  the  spinous  pro- 
cesses of  the  second,  third,  fourtli,  fifth  or  sixth  dorsal 
vertebrae,  the  internal  face  of  the  cartilage  of  the  scap- 
ula. Action :  Draws  the  shoulder  upwards  and  for- 
wards. 

3.  Anoularis  scapula. — Synonyms.  Trachelo-sub- 
scapularis,  (G).  Anterior  portion  of  the  serratus 
magnus,  (P).  Attachments  :  The  transverse  processes 
of  the  five  last  cervical  vertebrse,  the  anterior  triangu- 
lar surface  of  the  internal  face  of  the  scapula.  Action : 
Pulls  the  scapula  forward,  may  assist  in  the  lateral 
inclination  of  the  neck. 

4.  Splenius. — Synonyms.  Cervico-trachelian,  (G). 
Attachments:  The  ligamentum  nuchse,  the  summit  of 
the  spinous  processes  of  the  first  dorsal  vertebrae,  the 
mastoid  crest  of  the  occipital,  the  transverse  processes 
of  the  atlas,  and  that  of  the  third,  fourth  and  fifth  cer- 
vical vertebrfB.     Action :  Extensor  of  head  and  neck. 

5.  Great    complexus. — Synonyms.      Dorso-occipi 
talis,    (G).      Complexus    major,    (P).      Attachments : 
The  summit  of  the  spinous  processes  of  the  first  dorsal 
vertebrse,  the  transverse  processes  of  the  two  first  dor- 
sal, the  articular  tubercles   of  the   cervical  vertebrae, 


NKCK.  123 

tlie  posterior  face  of  the  occipitfil  protuberance,  on 
eacli  side  of  the  cervical  tuberosity.  Action  :  Extensor 
of  the  head. 

6.  Small  complexus. — Synonyms.  Dorso-niastoid- 
ens,  (G).  Traclielo-mastoidens,  (P).  Attachments  • 
The  transverse  processes  of  the  two  first  dorsal  verte- 
brae, the  articular  tubercles  of  tlie  cervical  vertebrae, 
the  mastoid  process  of  the  temporal,  the  transverse 
process  of  the  atlas.  Action:  Extensor  of  the  head, 
which  is  carried  sideways. 

7.  Transverse  spinous  of  the  neck. — Synonyms. 
Dorso-spinalis,  (G).  Spinalis  colli,  (P).  Attachments ; 
On  the  five  last  articular  tubercles  of  the  cervical  ver- 
tebrae, the  superior  spinous  processes  of  the  sixth,  fifth, 
fourth,  third  and  second  cervical  vertebrae.  Action: 
Extensor  and  inclinator  of  the  neck. 

8.  Six  intertransyeesal  of  the  neck. —  Synonyms. 
Inter-cervical,  (G).  Not  described  by  P.  Attach- 
ments :  Upon  the  transverse  and  articular  processes  of 
the  cervical  vertebrae,  except  the  first.  Action  :  Incline 
the  neck  on  one  side. 

9.  Great  oblique  OF  THE  HEAD. — Synonyms.  Axoido- 
atloideus,  (G).  Obliquus  capitis  inferior,  (P).  At- 
tachments :  The  spinous  process  of  the  axis,  the  trans- 
verse process  of  the  atlas.  Action :  Kotator  of  the 
atlas  and  head. 


124  EQUINE    ANATOMY. 

10.  Small  oblique  of  the  head. — Synonyms.  At- 
loido-mastoideus,  (G).  Obliquus  capitis  superior,  (P). 
Lateral  atloido-oecipitalis,  (L).  Attacliments  :  To  the 
styloid  process  and  external  face  ,of  the  occipital  bone, 
near  and  on  the  mastoid  crest.  Action :  Inclines  and 
-extends  the  head. 

11.  Posterior  gkeat  steaight  of  the  head. — Syn- 
onyms. Long  and  short  axoido-occipitalis,  (G).  Kec- 
tns  capitis  posticus  major  and  complexes  minor,  (P). 
Attachments  :  Spinous  process  of  the  axis,  on  tlie  oc- 
cipital bone.     Action  :  Extensor  of  the  head. 

12.  Posterior  small  straight  of  the  head. — Syn- 
onyms. Atloido-occipitalis,  (G).  Rectus  capitis  posti- 
cus minor,  (P).  Atloido-occipitalis  superior,  (L).  At- 
tachments :  The  superior  face  of  the  atlas,  external 
face  of  the  occipital.     Action  :  Extensor  of  the  head. 

Inferior  region.— Eleven  muscles. 

1.  Subcutaneous  of  the  neck. — Synonyms.  Por- 
tion of  the  panniculus  carnosus,  (P).  Attachments  : 
Trachelian  cartilage  of  the  sternum,  the  lateral  surfaces 
of  the  superior  cervical  muscles,  the  zygomatic  crest. 
Action  ;  Braces  tlie  muscles  of  the  neck  and  pulls  the 
commissure  of  the  lips  backwards. 

2.  Mastoido-humeralis. — Synonyms,  Levator  hu- 
meri, (P).  Attachments:  The  mastoid  process  and 
crest,   the  humerus,  tlie   transverse  processes  of    the 


NECK.  125 

four  first  cervical  vertebrae.  Action  :  Carries  tlie  an- 
terior leg  forward  or  inclines  the  head  and  neck  to  one 
side. 

3.  Sterno-m AXILLARIS. — Attachments  :  The  anterior 
extremit}^  of  the  sternum,  the  posterior  border  of  the 
maxillary.  Action  :  Flexes  the  head  directly  or  to 
one  side. 

4.  Stern  0-HY0IDEU8.  6.  Sterno-thyroideus. — 
Synonyms.  Sterno-thyro-hyodens,  (P).  Attachments : 
The  anterior  extremity  of  the  sternnm,  the  body  of 
the  iiyoid  bone,  the  thyroid  cartilage.  Action  :  De- 
pressors of  the  hyoid  bone  and  of  the  larynx. 

6.  Omo  or  subscapulo-hyoideus — Synonyms.  Sub- 
scapnlo-hyoidens,  (P).  Attachments:  On  the  inner 
surface  of  the  subscapularis  muscle,  body  of  hyoid 
bone.     Action  :  Depressors  of  the  hyoid  and  larynx. 

7.  Great  anterior  straight  of  the  head. — Syno- 
nyms. Traehelo-snb-occipitalis,  (L).  Kectus  capitis 
anticus  major,  (P).  Trachelo-occipitalis,  (L).  At- 
tachments :  The  transverse  processes  of  the  third, 
fourth  and  fifth  cervical  vertebrae,  the  sphenoid  bone 
and  basilar  process  of  the  occipital.  Action  :  Flexes 
tlie  head  directly  or  to  one  side. 

8.  Small  anterior  straight  of  the  head. — Syno- 
nyms. Atloido-sub  occipitalis,  (G).  Rectus  capitis 
a.iticus  minor,  (P).     Atloido-occipitalis  inferior,   (L). 


126  EQUINE    ANATOMY. 

Attachments:  The  body  of  the  atlas,  the  basilar  pro 
cess  of  the  occipital.     Action  :  Cooperates  to  flex  tlio 
head. 

9.  Small  lateral  straight. — Synonyms.  Atloido- 
styloideuSj  (G).  Obliqnus  capitis  anticus,  (P).  Attach- 
ment :  To  the  atlas,  tlie  styloid  process  of  the  occipital. 
Action  :   Congener  of  the  other  straight  muscles. 

10.  Scalenus — Synonyms.  Costo-tracheleus,  (G). 
Attachments  :  The  transverse  processes  of  the  four  last 
cervical  vertebrae,  the  superior  extremity,  anterior  bor- 
der and  external  face  of  the  first  rib.  Action  :  Flexes 
the  neck  directly  or  to  one  side,  or  acts  as  an  assistant 
to  respiration. 

11.  Long  muscle  of  the  neck. — Synonyms.  Sub- 
dorso-atloideus,  (G).  Longus  colli.  (P).  Dorso-at- 
loideus,  (L).  Attachments  :  The  body  of  tiie  first  six 
dorsal  vertebrae,  tlie  transverse  processes,  and  the  in- 
ferior spinous  processes  of  tlie  first  six  cervical  verte- 
brae, the  tubercle  of  the  inferior  face  of  tlie  atlas. 
Action  :  Flexor  of  the  neck  and  of  the  cervical  verte- 
brae individually. 

SPLAMH^OLOGY. 

Trachea. — Cartilaginous  tube  extending  from  tlie 
larynx  to  the  base  of  the  heart,  whore  it  divides  into 
the  right  and  left  bronchia.    Form  :  Cylindroid,  slightly 


NECK.  127 

flattened  from  above  below.  Connections  :  In  the  neck^ 
with  the  oesophagus,  carotid  arteries,  pneumo-gastric,. 
sympathetic  and  recurrent  nerves ;  in  the  thorax, 
above  to  the  longus  colli  and  oesopliagus,  below  to  the 
bronchial  trunks,  the  anterior  aorta,  anterior  vena  cava,, 
cardiac  and  recurrent  nerves,  base  of  the  heart ;  on  tlie 
sides,  to  the  inferior  cervical  ganglion  of  the  symp- 
athetic, to  tlie  vertebral,  superior  cervical  and  dorsal 
arteries  and  to  the  antei'ior  mediastinum ;  on  the  right 
to  the  vena  az3^gos ;  on  the  left,  to  tlie  cross  of  the 
aorta  and  the  thoracic  duct.  Structure  :  It  consists  of 
about  fifty  cartilaginous  rings,  united  by  inter-cartila- 
ginous ligament,  lined  by  a  mucous  membrane  covered 
by  ciliated  epithelium,  containing  muscular  fibres,  and 
receiving  blood  vessels  from  the  carotid  and  the  bron- 
chial trunks,  nerves  from  the  recurrent  and  sympathe- 
tic. 

Qilsophagiis. — Form  :  A  long  membranous  tube  con- 
necting the  pharynx  with  the  stomach,  it  is  placed 
above  and  to  the  left  of  the  trachea,  passes  into  the 
thorax  over  the  base  of  the  heart,  to  the  right  pillar  of 
the  diaphragm,  terminating  at  the  stomach  in  the  car- 
diac opening.  Connections  :  At  its  origin,  is  situated 
between  the  guttural  pouches  and  the  larynx ;  in  the 
neck,  above  between  the  trachea  and  the  longus  colli ; 
on  each  side  the  carotid  artery  and  its  nerves ;  below, 


128  EQUINE    ANATOMY. 

with  the  trachea,  scalenus  muscle,  blood  vessels  and 
nerves  of  the  neck ;  and  on  the  left  side  with  the  jug- 
ular vein ;  in  the  tliorax  with  the  inferior  cervical  gan- 
glion and  its  branches  ;  the  vertebral,  superior  cervical, 
and  dorsal  arteries  and  veins,  with  the  left  bronchia, 
aorta,  lung,  oesophageal  arterj  and  nerves.  Structure  : 
Two  coats  of  muscular  fibres,  a  mucous  membrane  with 
longitudinal  folds,  oesophageal  arteries  and  branches  of 
the  pneumo-gastric  nerve. 

Thyroid  Gland.— Composed  of  two  ovoid  lobes,  one 
on  each  side  of  the  lirst  two  rings  of  the  trachea,  united 
by  a  small  band  running  in  front  of  the  trachea.  Struc- 
ture :  A  fibrous  envelope,  parenchymtous  mass,  branches 
of  the  thyro-laryngeal  and  thyroid  accessorius  arteries 
and  nerves  from  the  first  and  second  cervical  pairs. 

AXGEJOLOGY. 

Arteries. — Fsimitive  carotid. — Branches  of  the 
cephalic  trunk :  E-unning  along  the  trachea  to  the  gut- 
tural pouches  and  the  larynx,  where  it  terminates  in 
the  arteries  of  the  head.  (See  page  102.)  Collateral 
brandies:  Innominated  to  the  oesophagus,  the  trachea 
and  the  cervical  muscles ;  the  thyro-laryngeal,  whicli 
runs  downwards  to  the  thyroid  gland  and  sends  branches 
to  the  larynx,  and  the  thyroid  accessorius  to  the  thyroid 
body  by  its  posterior  extremity. 


NECK.  1 29 

Veins. — The  jugular,  formed  by  the  superiicial  tem- 
poral and  the  internal  maxillary  vein,  runs  downwards 

and  backwards  in  the  inferior  extremity  of  the  neck, 
and  terminates  with  the  axillary  vein  to  the  gulf  of 
the  jugulars.  In  connection  above  with  the  parotid 
gland,  below  with  the  subscapulo  hyoideus,  panniculus 
carnosus,  trachea  and  to  the  left  side  the  oesophagus. 
Lymphatics. — They  come  from  the  pharyngeal  to 
the  prepectoral  ganglion  or  directly  to  the*  great  lym- 
phatic vein. 

NEUROLOGY. 

Eight  cervical  rachidian  pairs. — The  superior 
roots  go  to  the  muscles  of  the  superior  cervical  region 
and  the  cervico  and  tempero-auricularis  muscles  ;  the 
inferior  roots  of  the  six  first  pairs  anastomose  and 
form  by  their  branches  the  superficial  cervical  plexus  ; 
they  ramify  upon  the  sides  of  the  neck  and  the  mus- 
cles of  the  chest.  The  seventh  and  eighth  unite  to- 
gether, and  with  the  two  first  dorsal  form  the  brachial 
plexus. 

Sympathetic — Superior  cervical  ganglion. — Elon- 
gated and  fusiform  ;  it  runs  along  the  internal  carotid 
artery  in  a  fold  of  the  guttural  pouches  in  front  of 
the  transverse  process  of  the  atlas,  and  in  connection 
with  the  ninth,  tenth,  eleventh  and  twelfth  pairs  of 


130  EQUlNJfi    ANATOMY. 

cranian  nerves  forming  the  guttural  plexus.  Afferent 
branches  come  from  the  cranian  nerves ;  efferent 
branches,  to  the  internal  carotid  to  form  the  cavernous 
plexus;  to  the  primitive  carotid,  to  form  the  carotid 
plexus ;  to  tlie  fauces  and  the  pharynx,  forming  the 
pharyngeal  plexus.  Uniting  cord,  single  without  col- 
lateral branches  united  intimately  to  the  pneumogas- 
trie,  runs  down  with  it  and  ends  at  the  inferior  cervi- 
cal GANGLION.  This  ganglion,  larger  than  the  superior, 
is  situated  on  the  inside  of  the  scalenus  muscle,  is  of 
various  forms,  sometimes  single  or  double  forming  the 
middle  inferior  ganglion.  Afferent  branches  come 
from  the  cervical  pairs ;  efferent  branches,  form  the 
cardiac  nerves  (five  in  number),  and  in  front  of  the 
trachea  the  tracheal  plexus. 


CHAPTER  YIL 


THORAX. 


OSTEOLOGY. 

Dorsal  Vertebrae. — Genp:ral  characters:  Body 
very  short ;  head  wide  and  somewhat  flattened  ;  cavi- 
ty is  not  deep,  two  small  concave  articular  surfaces  on 
each  side  ;  superior  spinous  processes  are  very  high  and 
inclined  hackwards ;  transverse  processes  are  unituber- 
cular  with  a  flat  diarthrodial  facet;  the  articular 
facets  are  situated  at  tlie  base  of  the  spinous  process ; 
the  posterior  notches  are  very  deep. 

Specific  characters. — The  vertical  diameter  in- 
creases and  the  lateral  diminishes  from  forward  back- 
wards, the  articular  surfaces  of  the  body  are  wider  and 
flatter  as  they  go  backwards,  the  inferior  spinous  pro- 
cess is  well  developed  forward,  disappears  from  the 
sixth  to  the  ninth,  reappears  and  increases  to  the  last, 
the  intervertebral  cavities  diminish  from  the  first  to 
the  last,  the  superior  spinous  processes  increase  to  tlie 


132  EQUINE    ANATOMY. 

fifth,  then  diminish  to  the  last ;  their  obliquity  is  less 
pronounced  as  it  is  more  posterior,  the  articular  facets 
are  closer  to  the  median  line,  going  towards  the  tenth, 
and  increase  to  the  last ;  the  transverse  processes,  as  well 
as  the  articular  surfaces,  diminish  from  forward  back- 
wards ;   the  last  has  no  facets  on  the  posterior  border. 

Ribs. — Elongated  bones,  eighteen  on  each  side,  leaving 
between  them  the  intercostal  spaces,  and  being  pro- 
longed downwards  by  the  costal  cartilages. 

General  characters. — Division :  A  middle  part 
and  two  extremities.  Middle  part :  External  face  has 
a  groove  in  front  and  muscular  impressions  above. 
Internal  face  is  concave  and  smooth.  The  anterior 
border  is  concave  and  sharp,  the  posterior  convex,  thick 
and  with  vasculo-nervous  fissure.  The  superior  ex- 
tremity has  a  head  formed  of  two  convex  facets, 
separated  by  a  groove  and  a  tuberosity  with  a  flat  dia- 
throdial  facet.  Tlie  inferior  extremity  has  a  small 
irregular  cavdty.  Development :  three  nuclei,  one  for 
the  head,  one  for  the  tuberosity,  one  for  the  balance 
of  the  bone. 

Specific  characters. — Division  :  Eight  sternal  or 
true  ribs,  ten  asternal  or  false  ribs  ;  their  length  in- 
creases from  the  first  to  tlie  ninth,  then  diminishes  to 
the  last,  their  width  increases  from  the  first  to  the  sixth, 
then  diminishes  backwards,  their  curve  is  shorter  and 


THORAX.  133 

more  marked  as  it  is  more  posterior,  the  groove  of 
the  external  face  becomes  less  marked  as  th&  rib  is 
narrower. 

First  rib — Has  no  groove  on  the  external  face,  no 
fissure  between  the  facets  of  the  head,  shows  large 
muscular  impressions  on  the  external  face,  and  an  ar- 
ticular facet  on  the  inferior  extremity  of  the  internal 
face. 

Last  rib — Has  no  groove  externally,  the  facet  of 
the  tuberosity  and  the  posterior  facet  of  the  head 
are  united. 

Costal  Cartilages.— Those  of  the  eight  first  ribs  rest 
on  the  sternum  by  a  facet  after  articulating  above 
with  the  inferior  extremity  of  the  rib.  Those  of  the  false 
ribs  are  united  with  their  corresponding  ribs  by  their 
inferior  extremity,  which  terminates  in  a  point,  and 
rests  directly  upon  each  other. 

Sternum.— Situation:  under  the  thorax.  Division: 
Three  faces,  three  borders,  two  extremities.  The  su- 
perior face  is  concave  and  triangular ;  the  lateral  face 
is  divided  into  a  superior  portion  which  shows  diar- 
throdial  cavities  and  an  inferior  portion  for  muscular 
attachments.  The  lateral  border  separates  the  latter 
from  the  superior  face  ;  the  inferior  border  is  convex, 
thin  and  resembles  tlie  keel  of  a  ship.  The  anterior 
extremity  forms  tlie  trachelian  prolongation  ;  the  pos- 


134  EQUINE    ANATOMY. 

terior  extremity  forms  the  x^^phoid  cartilage  flattened 
from  above  below.  Structure  :  bony  and  cartilaginous. 
Development :  six  nuclei, 

SYIVDESmOLOOY. 

Intervertebral  joints.  (See  cervical  region,  page 
120.) 

Vertebro-costal. — Arthrodia. — Formed  by  the  fa- 
cets of  the  head  of  the  ribs  and  the  cavities  on  each 
side  of  the  body  of  two  adjacent  vertebrse.  Ligaments  : 
interarticular  and  inferior  peripheric.  Two  synovial 
capsulse.     Motion,  sliding. 

CosTO-TRANSVERSAL. —  Arthrodia.  —  Articular  sur- 
faces. Facets  on  the  tuberosity  of  the  rib  and  trans- 
verse process  of  the  posterior  vertebrse.  Ligaments  : 
posterior  and  anterior  transverse  costal ;  one  synovial 
capsula.     Motion,  sliding. 

Chondro-costal. — Synarthrodial.  Articular  sur- 
faces, inferior  extremity  of  the  rib  and  superior  ex- 
tremity of   the  cartilage.    Ligament :  the  periosteum. 

Chondro-sternal. — Arthrodia.  Articular  surfaces  : 
the  inferior  extremity  of  the  true  I'ibs  and  the  cavities 
of  the  sternum.  Ligaments  :  superior  and  inferior 
sterno-costal.     One  synovial  capsula. 

Chondro-chrondral. — Attached  by  some  yellow 
elastic  ligament. 


THORAX.  135 

MYOLOGY. 

Spinal  Region. — Seven  pairs. 

1.  Trapezium. — Synonyms  :  Dorso  and  cervico-acro- 
mialis,  (G).  Attachments  :  The  funicular  cord  of  the 
cervical  ligament,  the  apex  of  the  superior  spinous  pro- 
cess of  the  first  dorsal  vertebrae,  the  tuberosity  of  the 
acromion  and  external  surface  of  the  scapular  aponeu- 
rosis. Action  :  Raises  the  shoulder  and  carries  it  for- 
wards or  backwards. 

2.  Greatdorsal — Synonyms:  Dorso-humeralis,  (G). 
Latissimus  dorsi,  (P).  Attachments  :  The  apex  of  the 
spinous  process  of  all  the  lumbar  and  fourteen  or  fif- 
teen last  dorsal  vertebrae,  internal  tuberosity  of  the  hu- 
merus. Action :  Carries  the  arm  backwards  and  up- 
wards. 

3.  Small  anterior  serrated. — Synonyms  :  Dorso- 
costalis,  (G).  Superficialis  costarum,  (P).  Anterior 
serrated,  (L).  Attachments:  The  summit  of  the  spi-  i 
nous  process  of  the  tliirteen  dorsal  vertebrae  follow-  ! 
ing  the  first,  the  external  face  of  the  anterior  border  of  i 
tlie  nine  ribs  following  the  fourth.  Action :  Inspir-  \ 
atory.                                                                                                          ' 

4.  Small  posterior  serrated. — Synonyms.  Lumbo- 
costalis,  (G).     Superficialis  costarum,  (P.)     Posterior  • 
serrated,  (L).     Attachments  :  The  spinous  processes  of                  \ 


136  EQUINE  ANATOMY. 

the  last  dorsal  vertebrae  from  the  tenth,  the  lumbar 
vertebrae,  posterior  border  and  external  face  of  the 
nine  last  ribs.     Action  :  Expiratory. 

5.  Ilio-spinalis. — Synonyms.  Longissimus  dorsi, 
(P).  Attachments :  The  lumbar  border,  external  an- 
gle and  internal  face  of  the  ilium,  sacro-iliac  ligament, 
sacrum,  spinous  processes  of  all  the  lumbar,  dorsal,  and 
last  four  cervical  vertebrae,  articular  facets  of  the 
lumbar  vertebrae,  the  transverse  processes  of  all  the 
dorsal  and  last  four  cervical  vertebrae,  costiform  pro- 
cesses of  the  lumbar  vertebrae,  external  surface  of  the 
fifteen  or  sixteen  last  ribs.  Action :  Extensor  of  the 
vertebral  column  ;  may  act  as  an  expirator. 

6.  Common  intercostal. — Synonyms.  Trachelo- 
costalis,  (G).  Transversal  costarum,  (P.)  Attach- 
ments :  The  external  face  of  the  ribs,  transverse  pro- 
cess of  the  last  cervical  vertebrae.  Action  :  Depresses 
the  ribs. 

T.  Transverse  spinous  of  the  back  and  loins. — 
Synonyms.  Transverso-spinous,  (G).  Spinalis  and 
semi-spinalis  dorsi,  (P).  Attachments:  The  lateral 
border  of  the  sacrum,  the  articular  processes  of  the 
lumbar  and  transverse  processes  of  the  dorsal  vertebrae, 
spinous  processes  of  the  sacral,  lumbar,  dorsal  and  last 
cervical  vertebrae.     Action  :  Extensor  of  the  spine. 

Costal  Region.— Fifty-four  pairs. 


THORAX.  137 

1.  Great  serratus. — Synonyms.  Costo-siibscapu- 
laris,  (G).  Posterior  portion  of  the  serratus  magniis, 
(P).  Attachments :  The  external  face  of  the  eight 
true  ribs,  the  anterior  and  posterior  triangular  surfaces 
of  the  internal  face  of  the  scapula.  Action  :  Suspen- 
sor  of  the  trunk,  and  may  act  as  inspirator. 

2.  Transverse  of  the  ribs. — Synonyms.  Costo- 
sternalis,  (G).  Lateralis  sterni,  (P).  Attachments : 
Sternum,  fourth  costal  cartilage  and  external  face  of 
the  first  rib.     Action  :  Expiratory. 

3.  Seventeen  external  intercostals. — Attach- 
ments :  Posterior  border  of  the  preceding  to  external 
face  of  succeeding  rib.     Action  :  Inspiratory. 

4.  Seventeen  internal  intercostals. — Attach- 
ments :  Anterior  border  of  the  posterior  to  posterior 
border  and  internal  face  of  the  anterior  rib.  Action  : 
Expiratory. 

5.  Seventeen  supercostals. — Synonyms.  Trans- 
verso-costalis,  (G).  Levatores  costarum,  (P).  Attach- 
ments: Trans\^erse  processes  of  the  dorsal  vertebrae 
and  external  face  of  the  ribs.     Action  :  Inspiratory. 

6.  Triangularis  of  the  sternum. — Synonyms.  Ster- 
no-costalis,  (G).  Sterno-costalis,  (P).  Attachments : 
Superior  face  of  the  sternum  and  internal  face  of  the 
cartilages  of  the  true  ribs  except  the  first.  Action : 
Expiratory. 


138  EQUINE    ANATOMY. 

Muscular  attachments  of  the  anterior  extremity 
to  tlie  trunk. 

Pectoral  or  Axillarj  jpeg|on.--J.  Superficial  pec- 
TORAL. — Synonyms,  ^^e^torfiho  trftnoFcrons,  (P).  Divis- 
ion :  1 — Sterno-li^eralis.  Attachment^:  Anterior  ap- 
pendix and  inferior  border  of  tlie  sternum,  anterior  crest 
of  theh^Kfiery^^^Aotion :  Adductor  of  the  forearm. 
2— SSrn^ap^^ii^oticus^  Attachments:  Entire  inferior 
boroerof  tlie  sternum,  anterior  ridge  of  the  humerusj 
fascia  of  tlie  external  face  of  the  anti-brachial  aponeu- 
rosis. Action  :  Adductor  of  the  leg  and  tensor  of  the 
aponeurosis. 

2.  Deep  pectoral. — Division :  1 — Sterno-trochineus. 
Synonyms.  Fectoralis  mao^nus,  (P).  Attachments: 
Tunica  abdominalis,  two  posterior  thirds  of  the  inferior 
border  of  the  sternum,  internal  tubercle  of  the  superior 
extremity  of  the  humerus.  Action  :  Draws  the  leg  back- 
wards. 2 — Sterno-prescapularis.  Synonyms.  Pectoralis 
^aiivns,  (P).  Attachments  :  On  the  side  of  the  sternal 
keel,  the  cartilages  of  the  three  or  four  first  ribs,  the 
aponeurosis  covering  the  antea-spinatus  muscle,  the 
cervical  angle  of  the  scapula.  Action :  Draws  the 
shoulder  backwards  and  downwards,  and  tensor  of 
the  scapular  aponeurosis. 


THOKAX.  139 

SPLAXCHIVOLOGV. 

Pleura. — Serous  membriine  lining  tlie  thoracic  cavity, 
forming  two  sacs  resting  on  each  otlier  and  the  medi- 
astinum. The  anterior  mediastinum  is  that  portion  sit- 
uated in  front  of  the  heart ;  tlie  posterior  is  the  one 
posterior  to  tliat  organ.  The  costal  pleura  lines  the 
internal  face  of  the  ribs;  the  diaphragmatic  pleura  lines 
the  anterior  face  of  the  diaphragm  muscle.  With  the 
mediastine  pleura,  they  form  the  parietal  layer  of  tliat 
serous  membrane.  The  pulmonary  pleura  covers  the 
external  face  of  the  lungs  and  forms  the  viceral  layer. 
This  membrane  receives  blood  vessels,  and  also  nerves 
from  the  sympathetic,  pneumogastric,  diaphragmatic 
and  intercostals. 

Bronchia. — Terminal  branches  for  the  trachea,  one 
for  each  luug,  they  divide  in  this  tissue,  aifecting  the 
dichotomic  division.  The  right  bronchia  is  the  largest. 
They  are  perfectly  cylindrical  to  their  end,  and'^Fe 
composed  of  cartilaginous  rings  formed  by  elongated 
small  pieces  of  cartilages  resting  upon  each  other  by 
their  extremities,  (tliese  disappear  in  the  smallest  tube,) 
and  of  a  muscular  layer  lining  the  whole  extent  of  the 
tube,  which  is  covered  by  a  mucous  membrane.  They 
receive  divisions  of  the  bronchial  arteries,  veins  and 
nerves.    Lymphatics  pass  to  the  bronchial  glands. 


140  EQUINE    ANATOMY. 

LungSi — General  disposition:  Essential  organs  of 
respiration,  divided  in  two  lateral  moieties,  described 
as  the  right  and  left  lung,  tlie  former  being  the  larger. 
Form :  Together  they  have  the  form  of  the  thoracic 
cavity,  each  representing  half  of  a  cone  with  two  faces, 
three  borders,  a  base  and  an  apex. 

Faces. — External  is  convex;  internal  offers  an  ante- 
rior part  resting  on  the  anterior  mediastinum,  an  exca- 
vation for  the  reception  of  tlie  heart,  the  root  of  the 
lungs  ;  a  posterior  part  resting  on  the  posterior  medias- 
tinum, the  thoracic  groove  and  oesophageal  fissure.  The 
right  lung  has  also  a  small  lobule  on  that  face.  Base  : 
Concave  and  moulded  on  the  anterior  face  of  the 
diaphragm ;  on  the  right  lung  it  has  a  deep  notch  for 
the  posterior  vena  cava.  Apex :  Forms  tlie  anterior 
lobule  of  the  lung.  Borders :  Superior  is  convex 
and  rests  in  the  vertebro-costal  groove ;  the  inferior 
is  thin,  with  a  large  notch  on  the  left  lung  for  the 
heart ;  tlie  posterior  bounds  the  base  or  diaphragmatic 
face.  Structure  :  Serous  envelope,  the  pleura.  Tissue 
proper,  of  a  rose  color,  soft  but  resisting,  elastic,  very 
light,  divided  in  small  lobules  by  conjunctive  partitions, 
each  lobule  being  formed  of  pulmonary  vesicles  col- 
lected and  comnmnicating  together  witli  a  bronchial 
tube ;  each  vesicle  has  a  membrane  proper  lined  by 
pavimentous  epithelium  and  is  covered  with    capillajy 


THORAX.  141 

vessels  on  its  surface.  The  blood  vessels  of  the  lungs 
are  functional  branches  of  the  pulmonary  artery  and 
nutritive  divisions  of  the  bronchial  arteries  and  veins ; 
the  nerves  come  from  the  sympathetic  and  pneumo- 
gastric;  the  lymphatics  are  arranged  in  superficial  and 
deep  layers. 

Heart. — General  view:  Hollow  muscle  divided  by 
a  longitudinal  septum  in  two  masses,  and  each  of  these 
by  a  transverse  groove  in  two  others,  forming  four  cav- 
ities, two  superior,  the  auricles,  two  inferior,  the  ven- 
tricles. Situation :  opposite  the  third  and  sixth  ribs, 
in  front  of  the  diaphragm.  Form:  conoid.  Direction: 
obliquely,  backwards,  downwards,  and  slightly  from 
right  to  left.  Size  and  weight :  ten  and  one  quarter 
inches  long,  seven  and  a  lialf  at  its  base  from  back- 
wards forwards,  and  five  to  five  and  a  half  from  side 
to  side  ;  the  average  weight  is  six  and  three-quarter 
pounds. 

External  aspect. — Yentricular  mass:  has  two  faces, 
right  and  left,  both  divided  by  a  super o-inferior  fissure 
in  two  portions,  the  posterior  of  which  forms  the  left 
ventricle.  Connected  through  the  pericardium  to  the 
pleura  and  hmgs,  this  mass  has  two  borders,  one  ante- 
rior, obliquely  backwards  ;  one  posterior,  almost  verti- 
cal. Its  apex  is  formed  by  tlie  left  ventricle.  Its  base 
has  two  arterial  and  two  auriculo-ventricular  openings. 


142  EQUINE    ANATOMY. 

Auricular  mass. — This  has  three  faces,  a  superior 
with  the  openings  of  the  anterior  vena  cava  and  azy- 
gos  in  front,  and  pulmonary  veins  behind ;  right  face 
with  the  openings  of  the  posterior  vena  cava,  coronary 
and  brachial  veins  ;  and  a  left  face  embracing  the  aorta 
and  pulmonary  arteries.  Its  extremities  are  anterior 
ciud  posterior,  its  base  resting  on  the  ventricular  mass. 

Internal  aspect. — Cardiac  septum  divided  into  au- 
ricular, with  the  cicatrix  of  the  foramen  of  Botal ;  and 
ventricular  much  thicker.  The  right  ventricle  has 
two  walls,  known  as  anterior  and  posterior.  They  have 
fleshy  columns  of  three  kinds ;  an  apex,  not  extending 
to  the  point  of  the  heart ;  a  base,  with  the  pulmonary 
opening  furnished  with  sigmoid  valves,  and  the  auri- 
culo-ventricular  opening  presenting  the  tricuspid  valve 
secured  by  its  borders  to  ventricular  walls  by  the  cordse 
tendinosse. 

The  right  auricle  presents  an  anterior  cul  de  sac 
furnished  with  fleshy  columns  of  the  second  and 
third  kinds  :  a  posterior  wall  showing  the  fossa  ovalis, 
an  external  wall  with  venous  openings,  and  internal 
wall  smooth,  a  superior  wall  with  venous  openings,  a 
base  having  the  auriculo- ventricular  opening. 

The  left  ventricle  has  its  walls  covered  with 
fleshy  columns ;  its  apex  forms  the  point  of  the  heart ; 
the  base  presents  the  aortic  opening,  with  tlie  sigmoid 


THORAX.  143 

valves  and  the  auriculo-ventricular,  witli  the  mitral 
valve. 

The  right  auricle  covers  the  auriculo-ventricular 
opening,  and  on  its  superior  face  has  the  openings 
of  the  pulmonary  veins,  from  four  to  eight  in  number. 

Structure :  Annular  fibrous  frame,  made  of  four 
bands,  one  for  each  orifice  at  the  base  of  the  ventricu- 
lar mass.  Muscular  tissue  composed  of  uniting  and 
proper  fibres  of  the  ventricles  and  auricles.  The  fibres 
proper  of  the  ventricles  form  a  cone  open  at  both  ends. 
The  uniting  fibres  cover  the  external  surface  of  the 
ventricles,  twist  around  them  and  penetrate  into  and 
line  the  inside  of  the  ventricular  cavities.  In  the  auri- 
cles the  uniting  fibres  form  two  thin  bands  goin^from 
one  to  the  other ;  tlie  proper  fibres  divide  into  fasci- 
culi disposed  in  rings,  round  the  auriculo-ventricular 
openings,  or  in  sphincters  round  the  openings  of  the 
veins.  Blood  vessels  are  represented  by  the  coronary 
arteries  and  veins.  The  nerves  come  from  the  great  sym- 
pathetic and  pneumogastric.  It  has  two  serous  mem- 
branes, an  internal  or  endocardium,  lining  the  cavities 
and  extending  into  the  cavity  of  the  blood  vessels ;  an 
external  or  pericardium,  having  a  fibrous  cone  for  a 
frame,  on  the  inside  of  which  is  spread  the  serous  mem- 
brane proper  or  two  layers,  parietal  covering  the 
fibrous  cone,  and  a  visceral  resting  on  the  lieart  itself. 


144  EQUINE     ANATOMY. 

This  membrane  receives  blood  from  the  mediastinal 
arteries  ;  it  has  also  some  lymphatics. 

AXGEIOLOGY. 

Arteries, — Pulmonary. — Kisesf  rom  the  right  ventri- 
cle, runs  upward  and  backwards  in  a  cm*ved  direction 
and  above  the  left  auricle  divides  in  two  branches,  one 
for  each  lung,  where  thej  ramify.  Connections :  To 
the  right  with  the  aorta,  in  front  and  behind  is  em- 
braced by  the  auricles  and  cardiac  vessels ;  near  its 
middle  is  united  to  the  aorta  by  the  obliterated  ductus 
arteriosus. 

Primitive  aorta. — Rises  from  the  left  ventricle, 
where  it  forms  the  sinuses  of  the  aorta,  runs  upwards 
and  slightly  forwards,  and  after  two  or  two  and  a  half 
inches  divides  into  the  anterior  and  posterior  aorta,  its 
terminal  brandies.  Connections :  On  the  right  with 
the  auricular  mass ;  on  tlie  left  with  the  pulmonary 
artery.  Its  collateral  branches  are  the  cardiac  or  cor- 
onary arteries,  divided  into  right  and  left.  The  right 
rises  in  front  of  the  primitive  aorta,  passes  under  the 
anterior  auricle  and  divides  into  a  vertical  branch 
placed  in  the  right  vertical  fissure  of  the  ventricular 
mass,  and  one  horizontal  running  in  the  horizontal 
groove.  The  left  rises  opposite  the  right,  passes  be- 
hind the  pulmonary  artery  under  the  left  auricle,  and 


THORAX.  145 

divides  into  two  brandies,  one  horizontal  and  one  ver- 
tical, disposed  like  the  ri2;ht  cardiac.  These  tv7o  arteries 
anastomose  with  those  of  the  opposite  side,  and  from 
their  division  send  collateral  branches  to  the  muscular 
tissue  of  the  heart. 

Anterior  aorta. — Tiie  shortest  of  the  terminal 
branches,  runs  obliquely  upwards  and  forwards  above 
the  right  auricle,  under  the  trachea  on  the  left  side  of 
the  anterior  vena  cava,  and  terminates  by  the  two 
branches : 

1.  Brachial  OR  axillary  artery. — Running  a  course 
forward,  between  the  layers  of  the  mediastinum  under 
the  trachea,  it  reaches  the  entrance  of  the  thorax,  twists 
round  the  first  rib,  into  the  axillary  space  and  becomes 
humeral  (see  page  31). 

It  gives  off  eight  collateral  branches : 

1  The  DORSAL. — Synonyms.  Dorso-muscular,  run- 
ning towards  the  second  intercostal  space,  through 
it  outside  the  thorax,  bends  slightly  backwards  and 
ramifies  into  the  muscles  of  the  anterior  part  of  the 
dorsal  region,  having  a  larger  branch  passing  for- 
ward and  upwards  near  the  superior  border  of  the  neck 
to  anastomose  with  the  superior  cervical.  It  gives  oif 
one  collateral  branch,  the  subcostal,  which  passes  into 
the  costo- vertebral  groove  backwards,  giving  off  the 
second,  third  and  fourth  intercostal  arteries,  and  tcrmi- 


146  EQUINE    ANATOMY. 

n:ites  in  forming  the  iiftli  alone  or  with  another  branch 
from  the  first  posterior  intercostal.  ■ 

2  The  SUPERIOR  CERVICAL. — Synonyms.  Cervico-mus- 
cular ;  runs  outside  the  thorax  through  the  first  inter- 
costal space,  passing  upwards  and  forwards  under  the 
complexus  major  muscle,  reaches  the  second  cervical 
vertebrse  and  anastomoses  with  the  occipito-muscular 
and  the  dorsal  arteries.  It  gives  for  collateral  branches 
the  first  intercostal,  muscular  and  tegumentary  brandies 
to  the  superi'.)r  cervical  regions. 

3.  The  VERTEBRAL. — Passiug  inside  the  first  rib,  out- 
side the  trachea  and  the  inferior  cervical  ganglion,  and 
under  the  transverse  process  of  the  seventh  cervical 
vertebrae,  enters  the  trachelian  foramen,  runs  forwards 
and  upwards  to  the  atlas,  where  it  anastomoses  with 
the  occipital.  Its  external,  superior  and  inferior  collat- 
erals go  to  the  muscles  of  the  neck  ;  its  internal  to  form 
the  median  spinal. 

4.  The  INTERNAL  THORACIC  OR  MAMMARY. — Descending 
inside  the  first  rib  to  the  sternum,  then  backwards  upon 
its  superior  face,  it  terminates  at  the  base  of  the  xyphoid 
cartilage  by  the  anterior  abdominal,  which  passes  out- 
side the  thorax  under  that  cartilage,  on  the  superior 
face  of  the  rectus  abdominis  muscle,  where  it  ramifies 
and  finally  anastomoses  with  tlie  posterior  abdominal, 
and  by  the  asternal  artery,  which  lies  inside  the  cartil- 


THORAX.  147 

aginous  circle  of  the  false  ribs,  runs  upwards,  sending 
intercostal  collateral  branches,  and  anastomoses  with 
the  thirteenth  intercostal.  The  mammary  furnishes 
superior  brandies  to  the  pericardium  and  pleura,  inferi- 
or branches  to  the  pectoral  muscles,  and  external  rami- 
fications to  anastomose  with  the  intercostals. 

5.  The  EXTERNAL  THORACIC. — Tumiug  over  the  an- 
terior border  of  tlie  first  rib,  it  runs  backwards  inside 
the  two  portions  of  the  deep  pectoral  muscles  in  which 
it  ramifies. 

6.  Tlie  inferior  cervical  or  trachelo-muscular. — 
Passing  outside  the  gulf  of  the  jugulars,  inside  the 
sterno-prescapularis,  it  terminates  by  an  ascending  and 
descending  muscular  branch. 

7  and  8, — Sus  and  subscapular.  Described  in  tlie 
arteries  of  the  anterior  extremity  (see  page  31). 

Posterior  aorta. — True  continuation  of  the  primi- 
tive aorta.  It  passes  upwards  and  backwards,  forming 
a  curve  called  the  arch  of  the  aorta,  reaches  the  left 
side  of  the  inferior  face  of  the  vertebral  column,  fol- 
lows the  vertebral  bodies,  gradually  coming  to  the 
median  line,  passes  through  the  diaphragm,  into  the 
abdomen  as  far  as  the  last  intervertebral  articulation, 
and  terminates  by  the  four  iliac  arteries.  Its  collaterals 
are  divided  into  thoracic  and  abdominal  branches. 

Thoracic  collaterals. — 1.  Intercostal  arteries:  Sev- 


148  EQUINE    ANATOMY, 

enteen  in  number.  Thirteen  are  from  the  thoracic  por- 
tion of  the  posterior  aorta,  the  iirst  from  the  cervical 
artery,  and  the  three  following  from  the  subcostal  (see 
page  145)  ;  they  run  through  the  intercostal  space  and 
divide  into  a  superior  or  dorso-spinal  artery,  an  ascend- 
ing branch  going  to  the  muscles  of  the  dorsal  region  ; 
and  an  inferior,  intercostal  proper,  or  descending 
branch  running  along  the  posterior  border  of  tlie  rib 
downwards  to  anastomose  with  branches  of  the  inter- 
nal thoracic,  of  the  anterior  and  posterior  abdominal 
and  even  circumflex  iliac  arteries.  The  intercostal  ar- 
teries form  the  parietal  branches  of  the  thoracic 
aorta. 

2.  Broncho- (ESOPHAGEAL. — Visceral  branch  of  the 
thoracic  aorta,  rises  from  the  convexity  of  the  arch 
of  the  aorta  and  near  the  bifurcation  of  the  trachea, 
gives  off  the  two  bronchial  arteries  ramifying  with  the 
bronchia ;  and  the  oesophageal,  divided  into  superior 
and  inferior,  which  run  above  and  below  the  oesophagus 
backwards  to  anastomose  with  branches  of  tlie  gastric. 

3.  Diaphragmatic — See  description  of  diaphrag- 
matic region,  page  151. 

Abdominal  collateral. — See  description  of  the  ab- 
dominal cavity,  page  59. 

Terminal  branches. — See  arteries  of  the  hind  ex- 
tremity and  pelvic  cavity,  pages  59  and  151. 


THORAX.  149 

Veins. — Cardiac  or  coronary. — The  small  cardiac 
empties  from  the  walls  of  the  right  ventricle  into  the 
right  auricle.  The  great  cardiac  empties  also  into  the 
right  auricle  inside  of  the  opening  of  the  posterior  vena 
cava,  after  receiving  the  bronchial  veins. 

Anterior  vena  cava. — Formed  by  the  two  jugulars 
and  the  two  axillary  veins,  terminates  on  top  the  right 
auricle,  receiving  in  its  course  the  internal  mammary, 
the  vertebral,  the  superior  cervical,  the  dorsal  and  the 
great  vena  azygos,  which  last  receives  the  first  lumbar 
and  intercostal  veins. 

Posterior  vena  cava. — See  description  of  the  ab- 
domen, page  172. 

Lymphatics. — Those  of  the  thoracic  cavity  consist  of 
three  ganglions:  1 — A  series  of  small  granulations 
placed  near  the  oesophagus  and  receiving  the  posterior 
lymphatics  of  this  organ  ;  2 — The  bronchial  ganglions, 
situated  at  the  bifurcation  of  the  trachea  and  receiving 
the  pulmonary  lymphatics ;  3 — Two  long  masses  of 
lobules  at  the  inferior  face  of  the  trachea,  into  whicli 
the  lymphatics  of  the  pericardium,  heart  and  a  part  of 
those  from  the  trachea  and  oesophagus  empty.  The 
lymphatics  of  the  tlioracic  walls  are  :  1 — A  mass  of 
small  granules  on  each  side  of  the  dorsal  column  ;  2 — 
A  large  mass  at  the  base  of  the  xyphoid  appendix ; 
3 — Some  small  ones  attached  to  the  thoracic  vessels. 


150  EQtJINE    ANATOMY. 

NEUROLOGY. 

Seventeen  pairs  of  dorsal  nerves  from  the  spinal  mar- 
row, all  of  which  are  alike,  having  a  superior  branch, 
running  towards  the  spinous  process  of  the  dorsal  ver- 
tebrae, ramifying  in  the  spinal  muscles  and  the  skin  of 
the  dorso-lumbar  region;  and  an  inferior  branch  which 
runs  downwards  between  the  intercostal  spaces  and  end 
in  the  intercostal,  pectoral  and  abdominal  muscles.  The 
first  and  second  pair  cooperate  to  form  the  brachial 
pelxus  (see  page  63). 

Dorsal  portion  of  the  sympathetic. — From  the 
inferior  cervical  ganglion  to  the  diaphragm  it  forms 
a  double  chain  of  ganglions,  seventeen  in  number,  situ- 
ated in  the costo-vertebral  groove,  continued  posteriorly 
by  the  lumbar  sympathetic.  It  has  afferent  branches 
coming  from  the  dorso-spinal  nerves  and  efferent 
branches  in  small  number,  among  which  the  small  and 
great  splanchnic  only  are  important.  The  latter  leaves 
the  main  trunk  near  the  sixth  or  seventh  ganglion, 
runs  backwards,  penetrates  the  abdomen,  where  it  ter- 
minates in  the  semi-lunar  or  solar  plexus  (see  abdomnal 
cavity,  page  174). 


CHAPTER  YIIT. 


DIAPHRAGMATIC    RKOION. 


Diaphragm.— Situated  between  the  thoracic  and  ab- 
dominal cavities,  obliquely  downwards  and  forwards. 
In  form  it  is  flattened  from  forwards  backwards,  wider 
above,  convex  on  its  anterior,  aud  concave  on  its  pos- 
terior faces.  It  is  divided  into  a  phrenic,  central  or 
aponeurotic  portion,  and  a  peripheric  or  fleshy  portion. 
Attachments :  By  the  tendons  of  its  two  fleshy  pillars 
on  the  bodies  of  all  the  lumbar  vertebrse,  by  its  fleshy 
peripheral  digitations  on  the  superior  face  of  the  xyphoid 
cartilage  and  the  internal  face  of  the  last  twelve  ribs 
near  their  inferior  extremity.  Structure  :  In  the  centre 
of  the  phrenic  portion  is  a  foramen  for  the  posterior 
vena  cava ;  through  the  right  pillar,  one  for  the  oeso- 
phagus; between  the  two  pillars  another  for  the  pos- 
terior aorta  and  tlioracic  duct.  Action :  Essentially 
inspiratory. 

ArterieSt — Diaphragmatic:  Two  or  three  small 
branches  coming  from  the  posterior  aorta  and  ramify- 
ing in  the  muscle. 


CHAPTER  IX. 


ABDOMEN. 


OSTEOLOGY. 

Lumbar  VERXEBRji:. — ^S^ls^^i.  General  characters  : 
They  are  longer  and  wider  than  the  dorsal ;  tlie  supe- 
rior spinous  process  is  short,  thin,  with  a  rough  crest 
on  the  apex ;  the  transverse  processes  are  very  large, 
liorizontal  and  flattened  from  above  below ;  the  ante- 
rior articular  facets  are  liollow  and  the  posterior  prom- 
inent and  tooth-like. 

Specific  characters. — The  vertical  diameter  of  the 
body  diminishes  and  the  transverse  diameter  increases 
from  forwards  backwards ;  the  transverse  processes  of 
the  first  and  second  incline  backwards,  the  third  and 
fourth  are  nearly  straight,  the  fifth  and  sixth  are  bent 
forward  and  are  quite  thick  ;  the  posterior  border  of 
the  fifth  has  a  wide  articular  facet,  the  sixth  has  one 
on  both  the  anterior  and  posterior  borders. 

SYJVDESMOLOGY, 

Articulation  of  the  two  last  lumbar  vertebrji:. — 
By  wide  facets  o^  the  bordei'S  of  the  transverse  processes 
forming  planiform  diarthrosis,  united  by  ligamentous 
fibres  and  with  one  synovial  capsula. 


ABDOMEiN^.  153 

MYOLOGY. 

The  muscles  of  the  abdomen  are  supported  exter- 
nally by  the  abdominal  tunic.  They  nnite  on  the  medi- 
an plane  forming  the  white  line,  and  are  four  in  num- 
ber. 

1.  Tunica  abdominalis. — A  vast  expansion  of  yel- 
low elastic  tissue,  spread  over  the  external  muscles, 
thick  near  the  pubis  and  along  the  wliite  line,  and  be- 
coming tliinner  towards  its  circumference.  Posteriorly 
it  becomes  lost  in  the  inguinal  region,  and  gives  origin 
to  the  testicular  envelope  known  as  the  dartos.  Ac- 
tion :  assists  the  abdominal  muscles  in  supporting  the 
intestinal  mass. 

2.  White  line. — Linea  alba.  Formed  by  the  inter- 
crossing of  the  aponeurosis  of  the  abdominal  muscles, 
it  extends  from  the  xyplioid  cartilage  of  the  sternum 
to  tlie  anterior  border  of  the  pubis. 

3.  Great  or  external  oblique  of  the  abdomen. — 
Synonyms :  Costo-abdominalis,  (G).  Qbliqus  externus 
abdominis,  (P).  Structure  :  fleshy  and  aponeurotic  por- 
tions. Attachments  :  fleshy  portion,  on  tlie  external 
face  of  the  thirteenth  or  fourteenth  last  ribs,  on  the 
aponeurosis  of  the  great  dorsal  muscle ;  by  its  internal 
border  it  gives  origin  to  its  aponeurosis ;  aponeui-otic 
portion,  on  the  linea  alba,  the  anterior   border  of  the 


154  EQUINE    ANATOMY. 

pubis,  posteriorly  it  divides  and  gives  origin  to  the 
crural  aponeurosis  and  the  crural  arch.  Action  :  Ex- 
piratory. 

Internal  crtjbal  aponeurosis. — Lines  the  internal 
face  of  the  leg,  covering  the  muscles  of  that  re- 
gion. 

Crural  arch,  Fallopius  or  Poupart's  ligament. — 
Extends  from  the  anterior  border  of  the  pubis  to  the 
external  angle  of  the  ilium.  Inside  of  the  pectineal 
insertion  of  the  small  psoas  muscle  it  forms  the  anterior 
line  of  the  crural  ring. 

Inguinal  canal. — An  inf  undibuliform  canal  through 
which  the  means  of  support  for  the  testicles  or  the 
external  mammary  vessels  pass  from  the  abdomen.  It 
presents  a  superior  and  an  inferior  opening. 

4.  Small  or  internal  oblique  of  the  abdomen. — 
Synonyms.  Ilio-abdominalis,  (G).  Obliquus  internus 
abdominis,  (1*).  Structure  :  like  the  preceding.  Attach- 
ments :  Fleshy  portion,  to  the  external  angle  of  the 
ilium  and  the  crural  arch ;  aponeurotic  portion,  to  the 
internal  face  of  the  cartilages  of  the  false  ribs,  and  the 
linea<ilba.     Action:  Expiratory. 

5.  Great  straight  of  the  abdomen. — Synonyms. 
Sterno-pubialis,  (G).  Rectus  abdoniinis,  (P).  Attach- 
ments :  the  cartilages  of  the  four  last  sternal  and  first 
asternal  ribs,  inferior  face  of  the  sternum,  the  internal 


ABDOMEN.  155 

face  of  the  great  oblique  and  the  anterior  border  of  the 
pubis.  Action :  Principal  flexor  of  the  vertebral 
column. 

6.  Transverse  muscle  of  the  abdomen. — Syno- 
nyms. Lumbo-abdominalis,  (G).  Transversalis  abdom- 
inis, (P).  Costo-abdominalis  internus,  (L).  Situated  on 
the  most  internal  part  of  the  abdominal  walls.  It  is 
attached  to  the  internal  face  of  the  false  ribs,  transverse 
process  of  the  lumbar  vertebra8e,|xyphoid  cartilage  of 
the  sternum  and  linea  alba.  Action  :  Compresses  the 
abdominal  organs  against  the  spine. 

Muscles  of  the  Sub-Lumbar  Region.— Nine  in  num 
ber,  covered  by  the  iliac  fascia  or  lumbo-iliac   aponeu- 
rosis. 

1.  Great  psoas. — Synonyms.  Sub-lumbo-trochineus, 
(G).  Lumbo-femoral,  (L).  Psoas  magnus,  (P).  Sit- 
uation :  under  the  transverse  processes  of  the  lumbar 
vertebrge.  Attachments  :  On  the  body  of  the  two  last 
dorsal  and  all  the  lumbar  vertebrse,  inferior  face  of  the 
two  last  ribs,  transverse  processes  of  the  lumbar  vertebrae 
and  internal  trochanter  of  the  femur.  Action :  Flexor 
and  rotator  of  the  thigh,  flexor  of  the  lumbar 
region. 

2.  Iliac  psoas. — Synonyms.  Ilio-trochineus,  (G). 
Iliacus,  (P).  Composed  of  two  fleshy  bodies.  Attach- 
ments :  On  the  iliac  surface,  external  angle  of  the  ili- 


156  EQUINE  ANATOMY. 

uni,  sacro-iliac  ligament,  ilio-pectineal  crest  and  the 
internal  trochanter.  Action :  Flexor  and  rotator  of 
the  thigh. 

3.  Small  psoas. — Synonyms.  Psoas  of  the  loins, 
(B).  Sub-lumbo  pubialis  or  iliacus,  (G).  Psoas  par- 
vus (P).  Lumbo-iliacus  (L).  It  is  semi-penniform. 
Attachments  :  On  the  body  of  the  three  or  four  last 
dorsal  and  of  all  the  lumbar  vertebrae,  ilio-pectineal 
eminence,  and  lumbo-iliac  aponeurosis.  Action  :  Flexor 
of  the  pelvis  on  the  spine,  arches  directly  or  laterally 
the  ischio-lumbar  region,  tensor  of  the  lumbo-iliac 
aponeurosis. 

4.  Square  muscle  of  the  loins. — Synonyms.  Sacro- 
costalis,  (G).  Sacro-lumbalis,  (P).  Attachments  :  The 
sacro-iliac  ligament,  posterior  border  of  the  last  rib, 
the  transverse  processes  of  the  lumbar  vertebrae,  the  in- 
ternal face  of  the  three  or  four  last  ribs.  Action  : 
Draws  the  ribs  backwards  and  inclines  the  lumbar  por- 
tion of  the  spine. 

5.  Inter-transversal  of  the  loins. — Synonyms. 
Inter-transversalis  lumborum,  (P).  Atta3hments :  The 
anterior  and  posterior  border  of  the  transverse  processes 
of  the  lumbar  vertebrae.  Action  :  These  five  muscles 
incline  the  lumbar  region  laterally. 


ABDOMEN.  157 

SPLAlVCHi\OLOG¥. 

Peritoneum. — A  serous  membrane  lining  the  abdom- 
inal cavity  and  forming  a  parietal  and  visceral  layer. 
The  former  passing  over  the  different  regions  of  the 
abdomen,  gives  rise  to  the  ligaments,  mesentery  and 
epiploon,  viz:  in  the  sus- sternal  region  it  forms  a  fal- 
ciform band  extended  from  the  umbilicus  to  the  liver ; 
passing  over  the  diaphragmatic  region,  it  forms  the 
right,  left  and  common  ligaments  of  the  liver,  the  car- 
diac ligament  surrounding  the  oesophagus;  behind  the 
liver  it  furnishes  the  hepato-gastric  ligament,  from 
which  rise  the  great  or  gastro-colic  and  gastro-splenic 
epiploon;  in  the  lumbar  region,  it  presents  the  hepa- 
tico-renal  ligament,  that  of  the  lobe  of  Spigel,  the  great 
mesentery  proper  supporting  the  small  intestine,  the 
colic  mesentery,  meso-coecum  and  meso-colon.  Tovrards 
the  pelvic  cavity  it  forms  the  three  ligaments  of  the 
bladder  ;  in  males  it  covers  the  dilated  portion  of  the 
efferent  canals,  the  vesicula  seminalis  and  reflex 
round  the  rectum.  In  females  it  forms  three  liga- 
ments, called  wide,  round,  or  ligaments  of  the 
ovary. 

The  visceral  layer  forms  an  external  envelope  to  all 
the  abdominal  organs  except  the  kidneys. 

Structure  :  connective  tissue  covered  with  pavimen- 


158  EQUINE    ANATOMY. 

tous  epithelium,  blood  vessels,  lymphatics,  and  nerves 
from  the  diaphragmatic,  lumbar,  intercostal  and  great 
sympathetic  systems. 

ABDOMINAL  ORGANS. 

In  the  anterior  region  :  stomach,  liver  and  spleen. 
In  the  superior  region :  pancreas,  kidneys,  superre- 
nal  capsules  and  ureters.  In  the  right  and  left  hy- 
pochondriac, the  flanks  and  inferior  region,  the  in- 
testines. In  the  posterior  region  :  the  pelvis  and  its 
contents. 

Stomach. — Situation  :  posterior  face  of  the  dia- 
phragm. Dimension :  twelve  to  fifteen  quarts.  Form  : 
elongated,  laterally  flattened  from  forward  backward, 
curved  upon  itself  and  constricted  in  its  middle.  Divi- 
sion :  Two  faces,  two  curvatures  and  two  extremities. 
Faces,  convex  and  smooth.  Curvatures,  the  great  in- 
ferior, convex  and  gives  attachments  to  the  great  epip- 
loon ;  the  smaller  concave,  and  attached  to  the  liver  by 
the  hepato-gastric  ligament.  Extremities :  the  left 
forms  a  large  conical  tuberosity,  the  right  is  continued 
with  the  duodenum. 

The  internal  face  is  lined  by  mucous  membrane, 
varying  in  aspect  in  the  left  and  right  portion,  and  pre- 
sents two  openings,  the  cardiac  and  pyloric. 

Structure. — Serous  membrane  envelops  the  whole 


ABDOMEN.  159 

organ,  and  furnishes  the  great  epiploon,  cardiac  liga- 
ment and  hepato-gastric  ligament.  Muscular  coat  formed 
of  three  layers,  one  of  which  belongs  essentially   to  the 
right  extremity ;  the  left  has  three  coats.   Mucous  mem- 
brane, in  the  left  extremity  is  covered  with  white,  thick 
epithelium,  in  the  right  with  fine   simple  cylindrical 
epithelium.     In  its  structure  we  find  tubular,  mucous, 
and  pepsine  glands.  Arteries :  gastric,  splenic,  right  and 
left  epiploic  and  pyloric.     Yeins :  satellites  of  the  ar- 
teries.    Lymphatics,  emptying  in  the  reservoir  of  Pec- 
quet. Nerves,  from  the  pneumogastric  and  solar  plexus. 
Liver.— Situation  :  obliquely  downwards  and  to  the 
left,  to  the  right  of  the  diaphragmatic  region.    Weight, 
about  eleven  pounds.  Form  :  irregularly  elliptical,  flat- 
tened from  forward  backward,  thick  in  its  centre,  thin 
at  its  borders.     Division  :  In  three  lobes.     The  whole 
organ  has  two  faces  and  a  circumference.     The    ante- 
rior face  is  convex,  and  lias  a  groove  for  the  posterior 
vena  cava;  the  posterior  is  smooth  and  convex,  with  a 
groove  for  the  portal  vein,  hepatic  blood  vessels,  nerves 
and    ducts.      The    circumference    is    divided    into    a 
supej'ior  or  left  border,  offering  from  right  to  left    the 
right  ligament  of  the  liver,  the  groove  for  the  vena 
cava,  a  notch  for  the  oesophagus,  the  left  ligament  of 
the  liver.     The  inferior  or  right  border  presents  the 
two  notches  separating  tlie  three  lobes.  The  right  lobe 


160  EQUINE    ANATOMY. 

is  the  medium  in  size,  and  has  on  its  posterior  face  the 
lobule  of  Spigel ;  the  left  lobe  is  the  largest.  Mode  of 
attachment :  Four  ligaments,  one  for  each  lobe,  and  one 
to  the  phrenic  portion  of  the  diaphragm.  {Structure : 
Serous  membrane  covering  the  faces  entirely,  except 
over  the  fissures.  Fibrous  or  Glisson's  capsule,  an  en- 
velope dipping  into  the  hepatic  tissue,  and  sending 
from  its  internal  face  numerous  partitions,  which  pen- 
etrate between  the  hepatic  granulations.  Proper  tis- 
sue of  the  liver,  composed  of  polyhedric  granulations 
or  lobules,  in  each  of  which  are  found  the  hepatic  or 
biliary  cells,  biliary  ducts,  afferent  vessels,  branches 
of  the  portal  vein  and  hepatic  artery,  the  ramifications 
of  the  first  being  called  the  interlobular  or  sub  hep- 
atic veins ;  an  effervent  vessel  with  a  lobular  or  supra 
hepatic  vein,  lymphatic  and  connective  tissue.  Excre- 
tory apparatus  :  ductus  choledochus,  emptying  in  the 
duodenum.  It  is  composed  of  a  fibrous  membrane,  a 
cylindrical  epithelium  and  racemose  glands.  Blood 
vessels:  hepatic  artery.  Yeins:  postal  and  supra  hep- 
atic. Lymphatic :  abundant,  empty  in  the  sub-lumbar 
reservoir  of  Pecquet.  Nerves  :  from  the  solar  plexus, 
pneumogastric  and  diaphragmatic  filaments. 

Spleen. — Form:  falciform.  Direction  and  situation: 
to  the  left  of  the  diaphragmatic  region,  obliquely 
downwards  and  forwards.     Division :  Two  faces,  two 


ABDOMEN.  161 

borders,  a  base  and  an  apex.  Faces  :  external,  convex  ; 
internal  concave,  it  touches  the  large  colon.  Borders  : 
posterior  thin  and  convex ;  anterior  concave,  has  a  lon- 
gitudinal fissure  for  the  blood  vessels  and  nerves,  and 
gives  attachment  to  the  great  epiploon.  The  base  rests 
on  the  left  kidney,  and  receives  tlie  suspensory  liga- 
ment. The  apex  is  thin.  Weight,  thirty-two  ounces. 
Mode  of  attachments:  The  suspensory  ligament  and 
the  great  epiploon.  Structure  :  A  serous  membrane, 
peritoneal  covering ;  a  fibrous  tunic,  wliich  from  its  in- 
ternal surface  send  trabecules,  dividing  the  organ  into 
numerous  spaces,  in  which  tlie  splenic  pulp  is  con- 
tained, as  well  as  the  Malpighian  bodies.  Artery  : 
the  splenic.  Yeins :  its  satellites.  Lymphatics  :  on  the 
external  surface  of  the  organ.  Nerves :  from  the  solar 
plexus. 

Pancreas. — Abdominal  salivary  gland. — Situa 
tion  :  sub-lumbar  region,  forward  of  kidneys,  poste- 
rior to  liver  and  stomach.  Weight :  seventeen  ounces. 
Form  :  irregular  and  variable,  flattened  from  above  be- 
low and  traversed  by  the  pancreatic  ring.  Faces : 
superior  is  in  connection  with  the  aorta,  posterior  vena 
cava,  coeliac  trunk,  solar  plexus,  right  kidney  and  su- 
pra-renal capsule  ;  inferior  is  related  to  base  of  coecum 
and  tlie  colon.  Borders :  anterior  is  in  connection  with 
the  duodenum  and  left  sac  of   the  stomach  ;  posterior 


162  EQUINE    ANATOMY. 

has  a  notch  for  posterior  vena  cava.  Extremities  :  right 
adheres  to  the  duodennm,  left  looks  towards  base  of 
spleen.  Structure  :  Like  the  salivary  glands.  Excre- 
tory apparatus  consists  of  two  canals,  that  of  Wirsung 
and  its  accessorius ;  they  open  in  the  duodenum,  oppo- 
site each  otlier. 

Kidneys.— Situation :  To  the  left  and  right  of  the 
sub-lumbar  region,  the  right  being  more  forward  than 
the  left.  Form  :  riglit  is  like  the  heart  on  a  playing 
card,  the  left  resembles  a  haricot  bean.  Division  :  Two 
faces,  smooth  ;  three  borders,  internal  forms  the  fissure 
or  hilus.  Weight:  right,  about  twenty-seven  ounces, 
left,  twenty-five.  Internal  aspect :  a  horizontal  sec- 
tion sliows :  1.  The  renal  pelvis  with  the  sinus  renalis, 
the  crest,  and  laterally  the  arms  of  the  pelvis.  2.  Cor- 
tical, and  3.  Medullary  layers  of  the  tissue  proper. 
Structure :  a  fibrous  membrane,  external  envelope  ; 
tissue  proper  divided  into  cortical  and  medullary  layer. 
In  the  first  are  found  the  Malpighian  corpuscles,  in  the 
latter,  the  tubuli  urinriferi.  Blood  vessels :  renal  ar- 
tery and  vein.  Lymphatics  :  numerous.  Nerves :  from 
the  solar  plexus.  Development :  they  appear  early  in 
the  foetus. 

Ureters. — Form,  membranous  canals.  Origin:  the 
inf  undibulium  of  the  pelvis.  Termination  :  obliquely 
into  the  bladder,  through  its  muscular  coat.  Structure : 


ABDOMEN.  165 

three  coats,  an  external  of  connective  and  elastic  tis- 
sue, a  median  muscular,  an  internal  mucous. 

Ovaries. — Situated  in  the  abdominal  cavity,  hang- 
ing to  the  sub-lnmbar  region,  a  little  posterior  of  the 
kidneys.  Modes  of  attachments  :  a  fold  of  peritoneum 
or  broad  ligament.  Structure  :  a  serous  coat  perito- 
neal, a  tunica  albnginea  and  a  tissue  proper  divided 
into  medullary  and  cortical  layers ;  in  the  latter  are 
found  the  Graafian  vesicles,  composed  of  a  fibrous  en- 
velope and  a  granular  membrane,  which  contains  the 
ovulam  or  ovum.  Blood  vessels :  ramification  of  the 
utero-ovarian  artery.  Lymphatics  :  go  to  the  sub-lumbar 
ganglion.  Nerves  come  from  the  small  mesenteric 
plexus.  ^. 

Oviducts. — Fallopian  or  uterine  tubes.  Situation  : 
in  the  broad  ligament,  near  its  anterior  border  ;  begins 
at  the  ovary  by  the  pavilion  or  ostium  abdominale,  and 
terminates  in  the  cul  de  sac  of  the  uterine  horn  by  the 
ostium  uterinum.  Structure:  an  external  layer  of  se- 
rous membrane,  a  middle  muscular  and  internal  mu- 
cous. Functions :  carries  the  ovulum  to  the  uterus  and 
tlie  seminal  fluid  to  the  ovulum. 

Uterus, — Situation :  in  the  abdominal  cavity,  sub- 
lumbar  regions  at  tlie  entrance  to  the  pelvic  cavity. 
Division  :  A  body  and  two  cornua.  Body  has  two 
faces,  superior  and  inferior ;  an  anterior  extremity  or 


164  EQUINE    ANATOMY. 

fundus,  and  a  posterior  separated  from  the  vagina  by 
the  neck  or  cervix  of  the  uterus.  Tlie  cornua  have  an 
inferior  curvature,  a  superior,  shorter  ;  an  anterior  and 
posterior  extremity.  Modes  of  attachment :  A  sus- 
pensory or  broad  ligament.  Interior  offers  many  mu- 
cous folds  and  three  compartments  or  cavities,  one  for 
the  body,  two  for  the  cornua.  Tlie  former  is  prolonged 
in  the  vagina  hy  the  Jleur  epanouie.  Structure:  a  se- 
rous tunic  peritoneal,  a  muscular  coat  with  longitudi- 
nal and  circular  fibres,  a  mucous  membrane  raised,  into 
folds,  containing  many  simple  or  ramified  glands. 
Blood  vessels  :  branches  of  the  uterine  and  utero-ova- 
rian  arteries.  Lymphatics,  numerous.  Nerves  sup- 
ported by  the  small  mesenteric  and  pelvic  plexuses. 

Intestines« — Division  :  Small  and  large. 

Small  intestine. — Length,  twenty-four  yards.  Form, 
cylindrical.  Course,  from  the  right  sac  of  the  stomach, 
runs  forward,  turns  backwards  round  the  base  of  the 
ccecum,  passes  to  the  left  flank,  forms  many  circumvo- 
lutions, returns  to  the  right  and  ends  in  tlie  ccecum, 
below  the  origin  of  the  large  colon.  Mode  of  attach- 
ments: by  the  stomach,  coecum,  and  principally  the 
mesentery.  Interior  has  longitudinal  folds,  villi,  glan- 
dular and  follicular  openings,  communicates  with  the 
stomach  by  the  pyloric  opening,  and  with  the  coecum 
by  the  ileo-coecal  valve ;  near  the  former  it  shows  the 


ABDOMEN.  165 

openings  of  the  ducts  of  the  liver  and  pancreas.  Struc- 
ture :  a  serous  coat  expansion  of  the  mesentery  ;  a  mus- 
cular coat  of  two  layers,  one  longitudinal  superficial, 
the  other  circular  deep  ;  a  mucous  membrane  soft, 
spongy,  vascular  with  thin  cylindrical  epithelial  cells 
and  numerous  villi.  Glands  :  of  Brunner,  of  Lieber- 
kulm  or  Galcati,  solitary  glands,  aggregated  follicles 
or  glands  of  Feyer.  Blood  vessels  :  arteries,  from  the 
great  mesentery  and  coeliac  trunk.  Yeins  empty  into 
the  portal  vein.  Lymphatics  from  three  superposed 
networks  in  the  mucous  membrane,  l!^erves,  from 
tlie  solar  plexus. 

Large  intestine. — Division  :  Coecnm,  colon  and 
rectum.  Ccecum — Situation  :  the  right  hypocondriac 
region,  obliquely  downwards  and  forwards.  Dimen- 
sion, little  over  three  feet.  Capacity,  seven  and  a  half 
gallons  of  fluid.  Form  :  conical,  terminating  in  a 
point  inferiorly,  with  circular  furrows  interrupted  by 
four  longitudinal  muscular  bands.  Mode  of  attach- 
ment :  adhering  directly  to  the  sub-lumbar  region,  and 
to  the  origin  of  the  colon,  by  the  meso-ccecum.  In- 
terior presents  valves  or  transverse  ridges,  the  ileo- 
coecal  valve,  and  above  it  the  opening  of  the  colon. 
Structure :  a  serous  coat,  longitudinal  and  circular 
muscular  fibres,  a  mucous  membrane  with  solitary  fol- 
licles, glands  of  Lieberkuhn,  and  a  few  villi.     Blood 


166  EQUINE    ANATOMY. 

vessels :  the  coecal  arteries  and  veins.  Lymphatics, 
emptying  into  the  sub-himbar  receptacle.  Nerves,  from 
the  great  mesenteric  plexus. 

Colon. — Division :  Large,  double  or  fixed,  and  small 
or  floating. 

Laege  colon. — Length,  ten  to  thirteen  feet.  Capacity, 
eighteen  gallons.  Form  and  general  disposition  :  rep- 
resents a  large  canal  with  dilatations  and  contractions, 
its  surface  being  crossed  by  longitudinal  bands  of  mus- 
cular tissue  and  folded  in  two;  each  part  being  itself 
doubled  in  its  turn,  thus  forming  four  portions.  Course: 
from  the  arch  of  the  eoecum,  the  first  portion  runs  for- 
ward to  the  posterior  face  of  the  diaphragm,  forms  the 
suprasternal  flexure,  turned  downwards  and  to  the  left; 
the  second  portion  continues  backwards  to  the  entrance 
of  the  pelvis,  where  inflected  to  the  left  it  forms  the 
pelvic  flexure  ;  the  third  portion,  running  forward  above 
and  to  the  left  of  the  second,  reaches  the  diaphragm 
and  forms  the  diaphragmatic  or  gastro-hepatic  flexure  ; 
the  fourth  portion  bound  to  the  first,  extends  upwards 
and  backwards  to  a  level  with  the  base  of  the  eoecum, 
where  it  ends  in  the  small  colon.  Modes  of  attach- 
ment :  by  the  meso-coecum  and  meso-colon,  by  its  ad- 
herence to  the  pancreas  and  eoecum  directly.  Internal 
surface  :  like  that  of  the  eoecum.  Structure  :  a  serous 
or  peritoneal  layer,  a  muscular  coat  in  two  layers,  and 


ABDOMEN.  167 

a  mucous  coat  like  the  coecum.  Blood  vessels  :  the  co- 
lic arteries  and  satellite  veins.  Lymphatics,  empty  in 
the  reservoir  of  Pecquet.  Nerves,  from  the  great  mes- 
enteric plexus. 

Small  colon. — Length :  ten  feet.  Form  :  like  the 
small  intestine  with  its  external  surface  bosselated,  and 
provided  with  tw^o  wide  longitudinal  muscular  bands. 
Course  :  from  the  terminal  end  of  the  large  colon  into 
the  left  flank,  ending  in  the  rectum.  Mode  of  attach- 
ment :  colic  mesentery.  Interior :  valvular  folds,  like 
tlie  coecum  and  colon.  Structure:  a  serous,  muscular 
and  a  mucous  coat,  like  tliose  of  the  colon.  Blood 
vessels  :  from  the  small  and  a  branch  of  the  great  mes- 
enteric artery,  veins  empty  into  the  postal  vein.  Lym- 
phatics :  as  numerous  as  in  the  small  intestine.  Nerves : 
from  the  posterior  mesenteric  plexus. 

Rectum, — See  pelvic  cavity,  page  177. 

AXGEIOLOGY, 

Artekies — ABDOMINAL  AORTA. — Continuation  of  the 
posterior  aorta  after  it  passes  through  the  diaphragm, 
terminating  at  the  lumbo-sacral  articulation  by  quad- 
rif urcation  forming  the  two  external  and  internal  iliacs. 
Its  collaterals  are  the  lumbar  and  middle  sacral  for 
parietal  branches,  the  coeliac  axis,  great  mesenteric, 


168  EQUINE    ANATOMY. 

renal,  small  mesenteric,  spermatic,  and  small  testicular 
for  visceral  branches. 

Ltjmbar — Five  or  six  in  number,  analogous  in  their 
course  and  disposition  to  the  inter-costals,  terminating 
by  superior  and  inferior  muscular  branches. 

Middle  sacral. — Often  missing,  and  when  found 
rises  between  the  two  internal  iliacs  and  runs  on  the 
inferior  face  of  the  sacrum  backwards,  losing  itself 
gradually. 

CcELiAc  AXIS. — Rises  from  the  inferior  face  of  the 
aorta  and  after  a  short  course  divides  into  three 
branches. 

1.  Gastric. — Passes  upon  the  left  extremity  of  the 
stomach  and  near  the  oesophagus,divides  into  an  ante- 
rior and  posterior  gastric,  both  ramifying  upon  the  cor- 
responding faces  of  the  organ.  It  gives  a  third 
branch  which  passes  along  the  oesophagus,  enters  the 
thorax  and  divides  into  two  branches,  which  anasto- 
mose with  the  two  oesophageal. 

2.  Hepatic. — Huns  outward  to  the  right  to  reach 
the  posterior  face  of  the  liver,  which  it  enters  dividing 
into  numerous  branches.  It  has  for  collaterals  the  pan- 
creatic, the  pyloric,  and  right  gastro-epiploic. 

a.  Pancreatic. — Small  branches  to  the  pancreas. 
h.  Pyloric — From  the  main  trunk  as  it  enters  the 
fissure  of  the  liver,  it  passes  towards  the  small  curva- 


ABDOMEJSr.  169 

ture  of  the  stomach,  and  anastomoses  round  the  pylorus 
with  the  posterior  gastric  and  right  gastro-epiploic. 

c.  Right  gastro-epiploic  or  omental. — Passes  along 
the  great  curvature  of  the  stomach  between  the  layers 
of  the  great  omentum,  and  anastomoses  by  arcade  with 
the  left  gastro-epiploic,  after  sending  gastric  and  omen- 
tal branches  or  collaterals.  It  furnishes  also  the  duo- 
denal, anastomosing  with  the  first  artery  of  the  small 
intestine. 

3.  Splenic. — The  largest  of  the  three  branches  of 
tlie  coeliac  trunk,  places  itself  in  the  fissure  of  the  inter- 
nal border  of  the  spleen,  down  to  its  apex,  runs  between 
the  two  layers  of  the  great  omentum  and  goes  to  anas- 
tomose with  the  right  gastro-epiploic,  having  thus  formed 
the  left  gastro-epiploic.  From  both  collateral  branches 
gastric,  splenic  and  epiploic  are  sent  in  all  directions. 

Great  mesenteric. — A  trunk  from  one  to  one  and 
a  half  inches  long,  rising  from  the  abdominal  aorta 
about  two  inches  behind  the  coeliac  axis,  and  soon  divides 
into  three  fasciculi,  left,  right  and  anterior. 

a.  Left  fasciculus. — Gives  fifteen  to  twenty  arte- 
ries, ramifying  in  the  small  intestines,  running  between 
the  layers  of  the  great  mesentery  and  at  some  distance 
from  the  small  curvature  of  that  organ,  dividing  into 
two  branches,  which  go  to  anastomose  with  correspond- 
ing branches  from  the  neighboring  arteries,  forming 


170  EQUINE    ANATOMY. 

arches  from  which  a  number  of  branches  start  to  rami, 
fy  in  the  intestinal  tract.  The  first  anastomoses  with 
the  duodenal,  and  the  last  with  the  ileo-coecal  artery. 

h.  Right  fasciculus. — A  short  trunk  which  soon  di- 
vides into  four  branches  : 

1.  Ileo-ccecal. — Anastomosing  with  the  last  artery 
of  the  left  fasciculus. 

2.  Two  ccECAL. — Divided  into  internal  or  superior, 
and  external  or  inferior.  Both  located  in  the  fissure 
of  the  coecum,  running  down  to  the  apex,  where  their 
divisions  anastomose  after  sending  collateral  branches 
to  the  organ.  At  its  origin  the  external  coecal  gives 
off  the  artery  of  the  coecal  arch  following  the  concavity 
of  the  arch,  where  it  disappears. 

3.  HiGHT  OR  direct  COLIC. — Ruus  iu  the  right  flex- 
ure of  the  colon  to  the  pelvic  curvature,  where  it  anas- 
tomoses with  the  left  colic,  furnishing  collateral 
branches  to  that  portion  of  the  large  intestine. 

c.  Anterior  fasciculus. — Furnishes  two  principal 
trunks  : 

1.  Left  colic  or  retrograde. — Acting  to  the  left 
portion  of  the  large  colon  as  the  direct  colic  does  for 
the  right,  and  anastomosing  with  it  at  the  pelvic  curv- 
ature. 

2.  First  artery  of  the  small  colon. — Placed  in 
the  posterior  fold  of  the  small  mesentery,  to  anasto- 


ABDOMEN.  171 

mose  with  the  first  division  of  the  small  mesenteric 
artery. 

d.  Innominated  branches — To  the  lymphatic  glands, 
supra-renal  capsules,  mesentery  and  pancreas. 

Small  mesenteric. — Descending  from  the  posterior 
abdominal  artery,  some  four  and  half  to  six  inches 
behind  the  great  mesenteric.  It  runs  between  the  lay- 
ers of  the  small  mesentery  and  forms  thirteen  or  four- 
teen branches,  which  act  somewhat  like  the  arteries  of 
the  small  intestines  and  ramifying  in  the  floating  colon 
and  rectum. 

Renal  or  emulgent. — One  for  each  kidney,  in  the 
substance  of  which  they  penetrate  by  its  notch  or  in- 
ferior face. 

Spermatic  or  great  testicular  in  the  male,  running 
outside  the  abdominal  cavity  into  the  inguinal  canal 
with  the  other  constituents  of  the  spermatic  cord,  and 
after  many  flexuosities  reaching  the  testicle,  in  which 
it  disappears ;  and 

Utero-ovarian  in  the  female ;  lodged  between 
the  folds  of  the  broad  ligament,  and  dividing  into  an 
ovarian  artery  to  the  ovary  and  a  uterine  to  the  cornu 
of  the  uterus. 

Small  testicular.— In  male;  distributed  to  the 
various  parts  of  the  spermatic  cord. 

Uterine. — In  female,  to  the  uterus  proper.     These 


172  EQUINE  ANATOMY. 

do  not  always  rise  from  the  abdominal  aorta,  but  more 
commonly  from  the  external  iliac. 

Veins. — Posterior  vena  cava. — Beginning  at  the 
pelvis  by  the  pelvic  crural  trunks  (see  page  182)  placed 
under  the  bodies  of  the  lumbar  vertebrae,  reaches  the 
superior  border  of  the  liver,  passes  through  the  phren- 
ic portion  of  the  diaphragm  to  the  posterior  and  ex- 
ternal part  of  the  right  auricle  of  the  heart,  being 
thus  divided  into  a  sub-lumbar,  hepatic  and  thoracic 
portions.  The  numerous  collateral  afferents  are :  the 
diajDhragmatic,  the  vena  portse,  the  renal,  the  sperma- 
tic and  several  lumbar  veins.  The  vena  portse  does 
not  empty  directly  into  the  vena  cava,  but  indirectly 
by  the  supra  hepatic  veins,  which  rise  from  its  subdi- 
vision, the  subhepatic  veins.  It  is  constituted  by  three 
principal  roots :  the  great  and  small  mesenteric  and 
splenic  veins;  it  receives  as  collateral  affluents  the 
right  gastro-epiploic  and  the  anterior  gastric  veins. 

Lymphatics. — 1.  Those  of  the  rectum  and  floating 
colon  are  placed  at  the  base  of  the  tail  on  each  side 
of  the  spliincter,  also  along  the  small  cui'vature  of  the 
rectum  and  between  the  folds  of  the  mesentery. 
Their  efferent  branches  unite  to  the  divisions  of  the 
sublumbar  ganglions. 

2.  Those  of  the  folded  colon  form  a  double  chain 
on   the   tract  of  the    colic   arteries.     Their   branches 


ABDOMEN.  173 

unite  to  those  of  the  small  intestines,  and  empty  in 
the  reservoir  of  Pecquet. 

3.  The  lymphatics  and  ganglions  of  the  coecum  are 
on  the  course  of  the  arteries.  Their  branches  unite 
to  the  trunk  of  the  small  intestine. 

4.  The  small  intestine  has  some  thirty  ganglions 
placed  in  the  thickness  of  the  mesentery  near  the 
origin  of  the  great  mesentric  artery ;  they  all  empty 
in  the  reservoir  of  Pecquet. 

5.  The  stomach  has  large  ganglions  on  the  small  and 
smaller  ones  on  the  large  curvature.  Their  efferent 
branches  empty  some  directly  in  the  thoracic  duct, 
some  after  uniting  with  the  anterior  trunk  of  the  intes- 
tinal lymphatics. 

6.  The  spleen  offers  several  ganglions  in  its  fissure, 
from  which  efferent  vessels  go  to  the  thoracic  duct. 

7.  Tlie  liver  presents  a  few  in  the  posterior  fissure, 
whose  vessels  unite  to  those  of  the  stomach  and 
spleen. 

Thoracic  duct. — General  confluent  of  all  the  lym- 
phatics of  the  body  except  those  of  the  right  anterior 
leg,  right  half  of  the  head,  neck  and  thorax.  It  ex- 
tends from  the  first  lumbar  vertebrae  to  the  entrance 
of  the  thorax,  beginning  by  the  sub-lumbar  reservoir 
or  cistern  of  Pecquet  on  a  level  with  the  great  mesen- 
teric artery.     Course  :  from  the  reservoir  passes  be- 


174  EQUINE    ANATOMY. 

tween  tlie  pillars  of  the  diapliragm,  and  in  various 
ways  arrives  towards  the  sixth  dorsal  vertebrae,  where 
it  leaves  the  aorta,  crosses  the  azjgos  vein  between  the 
axillary  arteries,  comes  out  of  the  chest  and  then  ter- 
minates with  a  dilation  in  the  anterior  vena  cava  at 
the  juncture  of  the  two  jugulars. 

Great  lymphatic  vein. — Confluent  of  the  lymphat- 
ics of  the  right  leg,  right  half  of  the  head,  neck  and 
thorax.  It  opens  at  the  junction  of  the  jugulars  by 
one  or  two  openings,  alone  or  by  anastomosing  with 

the  thoracic  duct  proper. 

NEUROLOGY. 

Six  pairs  of  lumbar  nerves,  whose  superior  branches 
ramify  in  the  spinal  muscles  and  integuments  of  the 
lumbar  region  and  haunch.  The  inferior  ramify  in 
the  abdominal  muscles  and  the  region  of  the  flank. 
The  third  pair  furnishes  three  inguinal  nerves — one  in- 
ternal, two  external. 

Lumbar  portion  of  the  sympathetic. — Continuation 
of  the  dorsal  chain ;  it  has  the  same  aspect,  and  lies 
against  the  small  psoas  muscle,  runs  to  the  lumbo-sac- 
ral  joint,  where  it  becomes  the  sacral  portion.  Its  af- 
ferent  branches  come  from  the  lumbar   pairs.      Its 


ABDOMEN.  175 

efferent  brandies  collect  into  two  or  three  nerves,  and 
by  their  anastomoses  form  the  posterior  mesenteric 
plexus,  which  gives  branches  to  the  floating  colon  and 
rectum,  some  to  the  anterior  mesenteric  plexus,  and  to 
the  spermatic  arteries  forming  the  spermatic  plexus ; 
the  last  branches  co-operating  to  form  the  pelvic  plexus. 


CHAPTEH  X. 


PELVIS. 


OSTEOLOGY. 

Sacrum. — Formed  by  the  union  of  the  five  sacral  ver- 
tebrae. Division  :  Two  faces,  two  borders,  a  base,  an 
apex  and  a  central  canal.  Faces :  Superior  presents 
the  spinous  processes  forming  the  sacral  spine,  bent 
backwards  and  diminishing  in  length  posteriorly;  it 
offers  on  each  side  the  four  supra-sacral  foramina. 
The  inferior  face  is  smooth  and  shows  the  lines  of  sep- 
aration of  the  vertebrae,  and  on  each  side  the  four  sub- 
sacral  foramina.  The  borders  are  thick  and  concave, 
rough  posteriorly,  having  forward  a  broad,  rough  au- 
ricular surface,  to  articulate  with  the  ossa  innominata. 
The  base  offers  on  the  median  line  the  anterior  orifice 
of  the  sacral  canal  and  the  anterior  articular  head  of 
the  body  of  the  first  sacral  vertebrae ;  on  the  sides  the 
articular  processes  and  the  anterior  notches  of  that  ver- 
tebrae, and  outside  the  two  large  facets  for  articulation 


PELVIS.  177 

with  the  last  himbar  bone.  The  apex  presents  the  pos- 
terior opening  of  the  sacral  canal,  the  posterior  articu- 
lar cavity,  the  body  of  the  last  sacral  vertebrae,  the 
vestiges  of  the  articular  processes  and  the  posterior 
notches  of  that  vertebrae.  The  sacral  canal  is  a  part 
of  the  rachidian  canal,  triangular,  and  is  narrowing 
backwards. 

OssA  iNNOMiNATA — Scc  postcrior  extremity,  page  45. 

SYIVDESMOLOOY. 

Sacro-iliac  joint. — Arthrodia :  Facets  of  the  sides 
on  the  base  of  the  sacrum  and  tlie  facets  of  the  internal 
face  of  the  ilium.  Sacro-iliac,  superior  ilio-sacral,  in- 
ferior ilio-sacral,  sacro-sciatic,  or  ischiatic  ligaments. 
One  small  synovial  capsula.  Yery  limited  sliding 
motion. 

MYOLOGY. 

See  posterior  extremity,  page  52  and  following 
pages. 

SPLAX( ECOLOGY. 

Rectum. — Posterior  portion  of  the  digestive  canal 
and  continuation  of  the  floating  colon,  from  which  it 
differs  by  the  absence  of  ridges,  is  thicker  and  has 
more  dilatable  walls  and  is  susceptible  of  large  disten- 


178  EQUINE    ANATOMY. 

sion.  Modes  of  attachment :  the  meso-reetmn,  a  fold 
of  the  colic  mesentery,  a  fold  of  the  peritoneum,  the 
suspensory  ligaments  of  the  penis  and  a  triangular 
fasciculus  of  muscular  fibres,  a  prolongation  of  its 
fleshy  coat.  Structure :  a  serous  membrane,  a  fleshy 
coat  of  longitudinal  and  annular  fibres,  a  mucous  mem- 
brane with  transverse  and  longitudinal  folds  ;  arteries 
from  the  small  mesenteric  and  internal  pudic ;  nerves 
from  the  pelvic  or  hypogastric  plexus. 

Anus. — The  posterior  opening  of  the  digestive  ca- 
nal, pierced  at  the  posterior  extremity  of  the  rectum 
under  the  base  of  the  tail.  Structure  :  mucous  mem- 
brane of  the  rectum,  muscular  fibres  of  the  rectum 
forming  an  internal  sphincter,  an  external  sphincter, 
a  retractor  or  ischio-anal  muscle  and  the  skin,  fine 
and  very  adhering  to   the  muscular  tissue  underneath. 

Bladder — Form  :  ovoid  with  a  large  extremity  or 
rounded  cul  de  sac  turned  forward,  and  a  posterior 
extremity,  the  neck,  continued  hy  the  urethra.  Its 
average  weight  is  about  sixteen  ounces.  Modes  of  at- 
tachment :  a  fold  of  the  peritoneum  forming  the  three 
liofaments  of  the  bladder.  Its  interior  shows  the  vesi- 
cal  trigone.  Structure:  a  mucous  membrane  intern- 
ally,  a  muscular  coat,  longitudinal,  circular,  oblique  and 
spiroid  fibres,  and  a  serous  coat  in  its  anterior  region ; 
arteries  from  the  vesico-prostratic ;  nerves  from  the 


PELVIS.  ITU 

pelvic  plexus  and  some  inferior  branches  of  the   two 
last  sacral  pairs. 

Yagina. — Situation :  in  the  pelvic  cavity  between 
the  rectum  and  the  bladder.  Internal  surface  ridged 
bj  longitudinal  folds.  Structure  :  an  external  coat 
muscular,  an  internal  mucous ;  and  arteries  from  tlie 
internal  pudic ;  nerves  from  pelvic  plexus. 

YuLTA. — Situated  below  the  anus.  It  presents  an 
external  opening  with  two  lips,  a  superior  and  inferior 
connnissure ;  the  latter  lodges  the  clitoris  covered  by  a 
fold  of  mucous  membrane  called  the  prepuce.  At 
some  four  or  five  inches  from  this  external  opening  the 
meatus  urinarius  and  its  valve.  The  hymen  is  a  mem- 
brane which  separates  the  cavity  of  the  vagina  from 
that  of  the  vulva.  Structure :  a  mucous  membrane, 
an  erectile  body  named  the  vaginal  bulb,  the  posterior 
and  the  anterior  con^^trictor  muscles  of  the  vulva,  two 
muscular  ligaments  and  an  external  layer  of  skin. 

ANGEIOLOGY. 

Arteries. — External  iliac  or  crural  trunk. — Ex- 
ternal brancli  of  the  termination  of  the  abdominal 
aorta,  running  obliquely  downwards,  backwards  and 
outwards  to  be  continued  by  the  femoral.  Its  collat- 
erals are  the  small  testicular  or  uterine  (see  page  171) 


180  EQUINE    ANATOMY. 

and  the  circumflex  iliac  running  at  a  right  angle  out- 
wardly to  divide  into  anterior  and  posterior  branches, 
ramifying  in  the  abdominal  muscles. 

Internal  iliac  ob  pelvic  trunk. — Extends  from 
the  last  lumbar  vertebrae  downv^ards,  outwards  and 
backwards  to  the  insertion  of  the  small  psoas,  where 
it  terminates  by  the  obturator  and  the  iliaco-f emoral . 
Its  collateral  branches  are : 

1.  Umbilical — Almost  entirely  obliterated  in  the 
adult,  and  found  extending  to  the  fundus  of  the 
bladder,  placed  in  the  free  border  of  its  lateral  liga- 
ments. 

2.  Internal  pudic. — In  the  male ;  running  back- 
wards along  the  superior  border  of  the  internal  obtu- 
rator muscle,  into  the  pelvic  cavity  to  the  ischial  arch, 
where  it  terminates^  the  bulb  of  the  urethra.  Its 
principal  collaterals  are  the  vesico-prostatic,  which 
ramifies  iti  the  bladder,  and  the  vesicula  seminalis. 
In  the  female,  it  ends  in  the  vagina  by  rectal,  vulvar, 
vaginal  and  bulbous  branches ;  its  principal  collateral 
is  the  vaginal  artery. 

3.  Sub-sacral  or  lateral  sacral. — Runs  back- 
wards under  the  sub-sacral  foramen  to  the  posterior 
extremity  of  the  sacrum,  where  it  ends  by  the  ischia- 
tic  and  lateral  coccygeal  after  furnishing  collaterals  to 
the  surrounding  parts  and  four  spinal  branches. 


PELVIS.  181 

a.  IscHiATic. — Runs  through  the  ischiatic  ligament 
to  ramify  in  the  ischio-tibial  muscles. 

h.  Lateral  coccygeal. — Extends  backwards  to  tlie 
end  of  the  tail  between  the  caudal  vertebrae  and  the 
depressor  muscles  of  that  region,  giving  off  muscular 
and  cutaneous  collaterals. 

c.  Median  caudal — branch  from  the  right  lateral 
coccygeal  runs  between  the  two  depressor  muscles  of 
the  tail ;  backwards  to  its  end,  where  it  terminates. 

4.  Iliaco-muscular  or  ilio-lumbar.- — Passes  out- 
wardly between  the  psoas  iliacus  and  the  bone  that  it 
covers,  and  near  the  external  angle  of  the  ilium  term- 
inates by  muscular  branches. 

5.  Gluteal. — E-amifying  in  the  gluteal  muscles 
after  passing  outside  the  pelvic  cavity  through  the 
great  sciatic  notch.  "^ 

a.  Obturator. — Directed  backwards'aua  aovvuwaruis  # 
towards  the  obturator  foramen,  runs  through  it  and  ^^ 
divides  into  branches  to  the  internal  crural  and  ischio- 
tibial  muscles ;  amongst  these  branches  we  find  the 
cavernous,  which  creeps  backwards  and  inwards  towards 
the  crus  penis,  where  it  dips  and  furnishes  the  posterior 
dorsal  of  the  penis,  which  goes  along  the  superior  bor- 
der of  that  organ  to  anastomose  with  the  anterior 
dorsal.  V  4^ 

Iliaco-fb^ioral. — Passes    outwards    the   tendon   of 


kwards  anoaownwai^s^ 


182  EQtJINE    ANATOMY. 

the  psoas  parvus  above  the  origin  of  the  anterior  rectus 
muscle,  and  ends  in  the  patellar  muscles. 

Veins. — The  internal  iliac  formed  by  the  iliaco-f em- 
oral,  obturator,  iliaco-muscular,  gluteal,  lateral  sacral 
and  internal  pudic,  unite  with  the  external  iliac  to  form 
the  pelvi-crural  trunk. 

Lymphatics. — Empty  into  the  sub-lumbar  ganglions. 

IVEUROLOGY. 

Sacral  nerves — Five  pairs.  Superior  branches 
like  those  of  the  other  spinal  nerves.  The  inferior 
branch  co-operates  to  form  the  lumbo-sacral  plexus  (see 
abdominal  extremity,  page  63)  by  the  first,  second 
and  third  pairs;  the  fourth  constitutes  the  internal 
pudic,  and  the  fifth  the  anal  or  hemorrhoidal  nerve. 

Sacral  portion  of  the  sympathetic. —  Formed  by 
four  ganglions  united  by  branches  communicating 
with  the  spinal  sacral  nerves,  and  at  the  posterior  ex- 
tremity of  which  starts  a  last  nerve,  the  end  of  the 
sympathetic  cordon,  wliich  terminates  in  various  ways. 


CHAPTER  XI. 


CA.Ur)i^L   REGIOISr. 


OSTEOLOGY. 

Caudal  vektebjrjs. — Fifteen  to  eighteen  in  number, 
in  which  tlie  general  characters  of  the  vertebrse  are 
easily  recognized  in  the  anterior  ones,  but  which  by 
degrees  disappears  till  the  last,  where  it  constitutes  a 
small  elongated  somewhat  conical  bone. 

SYJ^DESMOLOGY. 

Articular  surfaces  are  the  facets  of  the  bodies  of 
the  vertebrae.  Means  of  union  are  an  inter  articular 
cartilaginous  meniscus  and  longitudinal  ligamentous 
fibres. 

MYOLOGY. 

Three  sacro-coccygeal  and  one  ischio-coccygeal  mus- 
cles. 

1.  Sacro-coccygeal  superiok. — Synonyms.  Erec- 
tor coccygis,  (P).  Attachments :  Summits  and  sides 
of  three  or  four  last  processes  of  the  sacral  spine  and 


18i  EQUINE    ANATOMY. 

coccygeal  vertebrae.     Action:   Elevates   or   pulls  the 
tail  to  one  side. 

2.  SACRO-coccYaEAL  INFERIOR. — Sjnonjms.  Depres- 
sor coccjgis,  (F).  Attachments :  The  inferior  face  of 
the  caudal  vertebrae.  Action:  Depresses  or  inclines 
the  tail  to  one  side. 

3.  Sacro  COCCYGEAL  LATERALIS. — Sjnonyms.  Cur- 
vator  coccygis,  (P).  Attachments  :  The  spinous  pro- 
cess of  tlio  last  lumbar  vertebrae  and  of  the  caudal 
vertebrae.     Action  :  Inclines  the  tail  sideways. 

4.  IscHio-coccYGEAL. — Syuonyms.  Compressor  coc- 
cygis, (P).  Attachments :  The  sacro-ischiatic  liga- 
ment, the  ischiatic  crest  and  the  sides  of  the  last  sac- 
ral and  two  first  caudal  vertebrae.  Action  :  Depresses 
the  entire  caudal  appendage, 

AIVGEIOLOGY. 

Arteries. — Lateral  and  median  caudal  (see  page  181). 
Veins. — Satellites  of  the  arteries. 

NEUROLOGY. 

Nerves — Six  to  seven  pairs.  They  form  by  the 
union  of  their  branches,  two  long  nerves,  one  under 
the  depressor  of  the  tail,  the  other  under  the  sacro- 
caudal  lateralis,  which  lose  themselves  into  the  liga- 
ments and  the  muscles  of  the  tail. 


CHAPTEH  XII. 


^FPEN  DIX. 


Genital  organs  of  the  male.— Situated  partly  in  the 
inguinal  region,  in  the  pelvic  cavity  and  between  the 
two  internal  crural  regions. 

Testicular  envelopes— Scrotum. — Single  cutaneous 
pouch  covering  the  two  testicles,  thin,  covered  with  short 
fine  hairs  and  lubricated  by  unctuous  secretion  of  se- 
baceous follicles. 

Dartos. — Contractile  tissue,  one  for  each  testicle, 
resting  on  each  other  on  the  median  line,  separated 
above  for  the  passage  of  the  penis ;  covered  externally 
by  the  scrotum,  to  which  it  is  adherent,  and  covering 
the  fibrous  and  erythroid  tunics.  It  is  composed  of 
elastic  and  unstriped  muscular  fibres. 

Cremaster  or  tunica  erythroides. — Bright  red 
band  attached  above  to  the  peritoneal  surface  of  the 
lumbar  aponeurosis,  expanding  below  and  terminating 
upon  the 

Fibrous  tunic. — (Infundibulum  fascia),  continuous 


186  EQUINE    ANATOMY. 

with  the  transversalis  fascia,  it  forms  the  most  com- 
plete covering  of  the  serous  parietal  layer  of  the  tuni- 
ca vaginalis,  to  which  it  is  closely  adherent. 

Tunica  vaginalis. — Diverticulum  of  the  abdomi- 
nal cavity,  and  lined  by  the  peritoneum.  Its  interior 
forms  a  serous  sac,  which  is  elongated  downwards,  in- 
wards and  backwards,  and  is  divided  into  a  parietal 
layer  which  lines  the  inside  of  the  fibrous  tunic,  and  a 
visceral  layer  covering  the  testicle  and  the  spermatic 
cord.  These  two  layers  are  made  continuous  by  a  pos- 
terior frgenum.  The  tunica  vaginalis  contains  usually 
a  certain  quantity  of  serous  fluid. 

Testicles. — External  conformation :  oval,  flattened 
sideways  and  suspended  at  the  extremity  of  the  sper- 
matic cord.  It  has  two  faces,  smooth  and  round,  an  in- 
ferior border  convex  and  free,  and  a  superior  border 
related  to  the  epididymis.  It  is  hanging  in  the  tunica 
vaginalis,  through  the  testicular  or  spermatic  cord, 
formed  by  the  spermatic  vessels  and  the  vas  deferens. 
Structure  :  1 — A  fibrous  covering  or  tunica  albuginea, 
which  is  thicker  towards  the  inner  border  of  the  organ 
where  it  forms  the  corpus  Higmori ;  this  membrane  is 
dense  and  inelastic  ;  2 — A  tissue  proper,  greyish  yellow 
pulp  contained  in  the  fibrous  envelope.  It  presents  the 
tubuli  seminiferi,  in  the  axis  of  wliich  are  perceived 
the  spermatozoa  and  the  remains  of  the  spermatic  cells. 


APPENDIX.  187 

A  section  of  the  testicle  shows  the  trabeculge  testis,  the 
straight  canaliculi  (vasa  recta),  the  rete  testis  continued 
into  the  epididymis  as  the  vasa  efferentia ;  3 — Blood 
vessels  :  tlie  spermatic  artery,  the  veins  from  the  pam- 
piniform plexus,  the  lymphatics  are  numerous  ;  4 — the 
nerves  come  from  the  sympathetic. 

Epididymis. — It  commences  in  the  excretory  canal  of 
the  testicle,  is  an  elongated  body  resting  upon  the  su- 
perior border  of  the  testicle,  having  a  middle  portion, 
flat  on  both  sides,  an  anterior  extremity,  head  or  globus 
major  and  a  posterior,  tail  or  globus  minor,  which  is 
continued  by  the  vas  deferens.  Structure  :  a  simple 
ciliated  epithelium  resting  on  a  proper  amorphous 
membrane,  placed  on  unstriped  circular  fibres  in  the 
efferent  ducts  ;  and  beyond  a  stratified  ciliated  epithe- 
lium, a  proper  membrane  and  two  layers  of  circular 
and  longitudinal  unstriped  fibres,  protected  by  a  fibrous 
tunic. 

Defere:nt  canal — vas  deferens. — A  flexuous,  then 
straight  duct,  running  from  the  globus  minor  to  the  in- 
side of  the  pelvic  cavity  through  the  inguinal  ring,  in- 
flected there  backwards,  suddenly  dilated  and  terminat- 
ing in  the  vesicula  seminalis.  Structure  :  a  mucous 
coat  internally,  covered  by  a  contractile  and  a  fibrous 
tunic. 

YESICULiE  SEMINALIS AND    EJACULATORY    DUCT. Sit- 


188  EQUINE  ANATOMY. 

uated  in  the  pelvic  cavity,  above  the  bladder  and  the 
vas  deferens,  it  has  a  middle  portion  covered  by  the 
rectum ;  an  anterior  extremity,  the  largest  forming  a 
cul  de  sac ;  a  posterior  extremity  tapering  to  a  narrow 
neck  and  receiving  at  an  acute  angle  the  termination 
of  the  vas  deferens.  Structure :  an  internal  mucous 
coat,  a  middle  muscular  and  an  external  fibrous. 

The  ejaculatory  ducts,  formed  by  the  union  of  the 
vesiculse  seminalis  and  the  vas  deferens,  terminate  in 
the  urethra  on  the  side  of  the  veru  montanum. 

Urethra. — A  membranous  canal  extending  from  the 
neck  of  the  bladder  to  the  end  of  the  penis.  Course: 
from  its  origin  backwards  in  the  pelvic  cavity,  there 
bonds  downwards  over  the  ischial  arch  between  the 
two  roots  of  the  corpus  cavernosum,  forward  to  the 
head  (glans)  of  the  penis,  terminating  by  the  urethral 
tube.  It  is  divided  into  an  intra  pelvic  or  membran- 
ous, and  an  extra  pelvic  or  spongious  portion. 

Interior. — Constricted  at  its  origin,  it  expands  at  the 
prostate  gland,  forming  the  cul  de  sac  of  the  bulb  or 
ventricle ;  tlien  contracts  over  the  ischial  arch,  and 
remains  of  the  same  size  to  the  end.  Behind  the  ure 
thral  tube  is  the  fossa  navicularis.  On  the  mucous 
membrane  it  presents  the  openings  of  the  prostrate 
gland,  the  urethral  ridge  or  veru  montanum  and  the 
excretory   canals   of    Cowper's  glands.     Structure :  a 


APPENDIX.  189 

mucous  membrane,  thin  and  having  longitudinal  folds ; 
an  erectile  envelope  or  corpus  spongiosum,  covering  the 
extra  pelvic  portion  only ;  muscles,  represented  by  that 
of  Wilson,  the  bulbo-cavernous  or  accelerator  nrinse, 
the  ischio-urethral  or  compressor  urinse  and  the  trans- 
verse perinei.  Blood  vessels,  the  two  dorsal  arteries  of 
the  penis  and  nerves  from  the  internal  pudic  and  great 
sympathetic. 

Perineal  aponeurosis. — Divided  into  superior  and 
deep  layers. 

Glands  annexed — prostate. — Situated  in  the  pelvic 
cavity  at  the  commencement  of  the  urethra ;  a  con- 
glomerated gland  whose  secretion  is  thrown  into  the 
urethra. 

Cowper's  glands — OR  SMALL  PROSTATE. — Situated  on 
each  side  of  the  urethra,  above  the  ischial  arch,  and 
covered  by  the  muscles  of  Wilson  and   ischio-urethral. 

Corpus  cayernosum. — Erectile  stalk,  base  of  the 
penis  and  support  of  the  urethra.  Situated  between 
the  thighs,  prolonged  beneath  the  abdomen,  attached 
to  the  ischial  arch  and  terminating  by  the  glans  penis. 
External  conformation :  it  offers  two  lateral  faces 
plane ;  a  superior  or  dorsal  border  rounded  ;  an  infe- 
rior or  urethral  channeled  for  the  reception  of  the 
urethra ;  a  posterior  extremity  with  two  roots  or  crura 
attached  to  the  ischial  arch,  and  covered  by  the  erector 


190  EQUINE  ANATOMY. 

penis  nniscle ;  and  an  anterior  extremity  forming  a 
blunt  point,  surrounded  by  the  spongy  tissue  of  the 
glands.  It  is  attached  by  the  two  crura  and  the  two 
suspensory  ligaments.  Structure  :  erectile  tissue,  com- 
posed externally  of  white,  elastic,  fibrous  envelope, 
sending  by  its  inner  face  numbers  of  lamellar  trabecu- 
Ise.  The  blood  vessels  are  the  dorsal  arteries  of  the 
penis.  Nerves  from  the  internal  pudic  and  great  sym- 
pathetic. 

Penis. — Male  organ  of  copulation.  Extending 
from  the  ischial  arch  between  the  thighs  and  the  two 
dartoid  sacs,  beneath  the  belly,  where  it  terminates. 
Divided  into  a  fixed  and  a  free  portion,  which  is  cov- 
ered by  the  cutaneous  fold  of  the  skin,  the  sheath  or 
prepuce.  The  free  portion  at  its  anterior  extremity 
presents  the  urethral  tube,  the  urethral  sinus  and  the 
sub-urethral  notch.  The  penis  has  two  suspensory 
and  retractile  cords,  composed  of  unstriped  muscular 
fibres,  which  draw  it  back  into  the  sheath  after  erec- 
tion. The  sheath  contains  a  large  number  of  sebace- 
ous or  preputial  glands,  secreting  an  unctuous  fatty 
matter,  the  smegma  preputii. 

Genital  organs  of  the  female — ovaries,  fallopi- 
an TUBES,  UTERUS,  VAGINA,  VULVA. — (Scc  abdominal 
and  pelvic  cavities,  page  163.) 

Mamm^. — Situated   in    the    inguinal    region,    they 


APPENDIX.  191 

form  two  hemisplierical  masses,  distinct  from  each 
other  and  having  in  their  centre  the  teat,  nipple  or 
mammillge.  Structm'c :  composed  of  a  yellow  elastic 
fibrous  envelope  ;  tliey  consist  of  a  glandular  tissue 
made  of  acini,  clustered  in  groups  around  the  lactifer- 
ous ducts,  which,  by  their  union,  open  in  the  galacte- 
forous  sinuses,  from  which  rise  the  true  excretory 
canals  of  the  glands.  Much  connective  tissue  unite 
these  acini.  The  arteries  of  the  mammse  come  from 
tlie  external  pudic ;  the  nerves  from  the  first  lumbar 
nerve.    Their  function  is  to  secrete  the  milk. 


CHAPTER  XIII. 


ARTERIAL  SUBDIVISION, 


MAIN  TRUNK. 

Primitive  aorta. 

Cardiac  arteries. 
Posterior  aorta. 


Intercostal. 

Lumbar. 

Diapliragmatic. 
Middle  sacral. 
Bronclio-cesopliageal. 

Bronchial. 
(Esophageal. 
Coeliac  axis. 

Gastric. 
Splenic. 

Hepatic. 

Great  mesenteric. 

Left  fasciculus. 


COLLATERAL. 


Rio^ht  and  left  cardiac. 


Intercostal,  diaphrag- 
matic, lumbar,  mid- 
dle sacral,  broncho- 
cesophageal,  coeliac 
axis,  great  and  small 
mesenteric,  renal, 
spermatic,  small  tes- 
ticular or  uterine. 


Innominated. 


Splenic,  gastric,  epi- 
ploic branches. 

Pancreatic  branches, 
pyloric  artery. 

Innominated. 


TERMINATION. 

Posterior  and  anterior 
aorta. 

External  and  internal 
iliacs. 


Inferior  intercostal 
proper,  superior  or 
dorso-spinal. 

Superior  and  inferior 
muscular  branches. 

Muscular  branches. 

Bronchial  and  oesoph- 
ageal arteries. 

Superior  and  inferior. 
Gastric,  splenic,  hep- 
atic. 
Anterior  and  posterior. 
Left  gastro  epiploic. 

Right  gastro  epiploic. 

Three  fasciculi — left, 
right  and  anterior. 

Arteries  of  small  in- 
testines. 


ARTERIAL  SUBDIVISION. 


193 


MAIN  TRUNK. 

Right  fasciculus. 

Anterior  fasciculus. 

Small  mesenteric. 
Renal,  or  emulgent. 
Spermatic,    or    utero 

ovarian. 
Small     testicular,    or 

uterine. 
Internal  iliac. 


Umbilical. 
Internal  pudic. 


COLLATERAL. 


Subsacral. 


Iliaco-muscular. 

Gluteal. 

Obturator. 


Artery  corpus  cavern- 

osum. 
Iliaco-muscular. 
External  iliac. 

Circumflex  iliac. 

Femoral. 


Anterior  pudic. 

Posterior  abdominal. 
External  pudic. 


Deep  muscular. 
Superficial  muscular. 


Umbilical,  internal  pu- 
dic, iliaco-muscular, 
gluteal,  subsacral. 

Yesico-prostatic,  mus- 
cular branches — 
(male).  Vaginal — 
(female). 

Innominated  branch- 
es. 


M uscular  branches, 
and  artery  of  corpus 
cavernosum. 


Small   testicular, 
cumflex  iliac. 


cir- 


Anterior  pudic,  deep 
muscular,  superfi- 
cial, small  muscular 
and  saphena. 


Muscular  branches. 


TERMINATION. 

Ileo  coecal,  two  coecal, 

right  colic. 
Left  colic,  first  artery 

of  floating  colon. 
Arteries  of  small  colon 

Uterine  and  ovarian. 


Obturator  and  iliaco- 
femoral. 

Vesical  branches. 
Bulbous  branches. 


Ischiatic,  lateral  cau- 
dal, median  from 
rio:ht  caudal. 


Muscular  branches. 


Posterior  dorsal  of  the 

penis. 
Muscular  branches. 
Femoral. 

Anterior  and  posterior 
muscular  branches. 
Popliteal. 


Posterior  abdominal, 
external  pudic. 

Subcutaneous  abdom- 
inal, anterior  dorsal 
of  the  penis  (male), 
mammary  (female). 

Muscular  branches. 

Muscular  branches. 


194: 


EQUINE  ANATOMY. 


MAIN  TRUNK. 

Small  muscular. 

Saphena. 
Popliteal. 

Posterior  tibial. 


Plantar. 

Anterior  tibial. 

Pedal. 

Perforating  pedal. 
Metatarsal  pedal. 

Digital. 


Ungueal  preplantar. 
Plantar. 


COLLATERAL. 

Medullary  of  the  fe- 
mur. 

Femoro-popliteal,  ar- 
ticular and  muscu- 
lar branches. 

Posterior  tibial  mus- 
cular branches,  tib- 
ial articular  branch- 
es, medullary  tibial, 
and  branches  to 
anterior  part  of 
hock. 

From  convexity  of  the 
anastomos  e  s  —  two 
superficial  innomin- 
ated,  two  deep  inter- 
osseous. 

Muscular  and  peroneal 
branches. 

Articular  and  cutane- 
ous branches. 

Ligamentous  and  cu- 
taneous branches. 

Articular  and  tendin- 
ous innominated, 
perpendicular  artery 
of  Percival,  artery 
of  plantar  cushion, 
coronary  plexus. 


TERMINATION. 

Muscular  branches. 

Cutaneous  branches. 
Anterior  and  posterior 
tibial. 

Two  plantar. 


Anastomose    together 
in  the  hock. 


Pedal. 

Perforating  pedal, 

metatarsal  pedal. 
With  plantar. 
Digital. 

Plantar  and  preplan- 
tar. 


Anterior  face  of  coffin 

bone. 
Plantar  circle. 


Anterior  aorta. 


Dorsal. 


D)rsal,    superior  cer- 'Brachial    or  axillary, 


vical,  vertebral,  in- 
ternal thoracic,  ex- 
ternal thoracic,  in- 
ferior cervical,  supra 
and  subscapular. 
Su")-costal,  second, 
tliird  and  fourth  in- 
tercostal. 


the  right  furnishes 
the  brachio-qephalic 
trunk. 


Muscular  branches. 


ARTERIAL  SUBDIVISION. 


195 


MAIN  TRUNK. 
Superior  cervical. 

Vertebral. 
Internal  thoracic. 


External  thoracic. 
Inferior  cervical. 


Supra-scapular. 
Subscapular. 


Humeral. 


Anterior  radial. 
Posterior  radial. 


Radio-palmar,  or  trunk 
of  interosseous  met- 
acarpal. 

Sub-carpal  arch. 


Collateral  metacarpal. 


COLLATERAL. 


First  intercostal. 


External,  superior  and 
inferior  muscular 
branches,  internal 
spinal. 

Superior  branch  to 
pericardium  and 
mediastinum,  inferi- 
or and  external  mus- 
cular branches. 


Branches  to  latissimus 
dorsi,  posterior  cir- 
cumflex of  the 
shoulder,  muscular 
branches. 

Prehumeral,  or  anter- 
ior circumflex  of  the 
shoulder,  deep  hu- 
meral, epicondyloid, 
artery  of  coraco- 
radialis. 

Articular  and  muscu- 
lar branches. 

Articular  and  muscu- 
lar branches,  inter- 
osseous of  fore- 
arm. 


Two  posterior  inter- 
osseous, two  anter- 
ior interosseous. 

Branches  to  supra-car- 
pal arch,  synovial 
and  tendinous  bran- 
ches anastomose  to 
anterior  and  poster- 
ior interosseous. 


TERMINATION. 

Anastomoses  with  oc- 
cipito-muscular  and 
dorsal. 

With  occipital. 


Anterior  abdominal, 
and  thoracic  or  as- 
ternal. 


Muscular  branches. 

Superior,  or  ascend- 
ing, and  inferior,  or 
descending. 

Muscular  branches. 

Muscular  branches. 


Anterior  and  posterior 
radial. 


At  knee  joint. 

Interosseous  metacar- 
pal, collateral  meta- 
carpal. 

Supra-carpal  arch,  sub- 
carpal  arch. 


Digital. 


196 


EQUINE  ANATOMY. 


MAIN  TRUNK. 
Digital. 
Carotid. 
Occipital. 
Occipito-muscular. 

Cerebro-spinal. 
Basilar  trunk. 


Median-spinal. 
Internal  carotid. 

External  carotid. 

Glosso-facial. 


Maxillo-muscular. 
Posterior  auricular. 

Superficial  temporal. 

Subzygomatic. 

Internal  maxillary. 


COLLATERAL. 


Thyro-laryngeal,  tliy- 

ro-accessorius. 
Prevertebral,  mastoid, 

atloido-muscular. 

Branches  to  me- 
dulla oblongata, 
branches  to  annu- 
lar protuberance, 
posterior  cerebel- 
lar artery,  anter- 
ior cerebellar  ar- 
tery, two  branch- 
es to  internal  car- 
otid. J 


Glosso-facial,  maxillo- 
muscular,  posterior 
auricular. 

Pharyngeal,  lingual, 
sublingual,  inferior 
and  superior  coro- 
nary, innominated 
branches. 


TERMINATION. 

Like  in  the  hind  ex- 
tremity. 

Occipital,  internal  and 
external  carotid. 

Occipito-muscular  and 
cerebro-spinal. 

Muscular  branches. 

"]  One  anterior  for  bas- 
i  ilar  trunk,  one  pos- 
I  terior      median-spi- 

J  nal,  with  posterior 
cerebral. 


Inferior  dental,  ptery- 
goid, tympanic, 
sphenoidal,  deep 
posterior  temporal, 
deep  anterior  tem- 
poral, ophthalmic, 
buccal,  staphyline, 
superior  dental,  na- 
sal. 


One  posterior  cere- 
bral. 

One  anterior  cerebral, 
one  median  cerebral. 

Superficial  temporal, 
internal  maxillary. 

One  ascending  and  one 
descending  branch. 


Muscular  branches. 
Muscular  and  parotid- 

ean  branches. 
Anterior  auricular, 

subzygomatic. 
Transversal    of     the 

face  and  masseter- 

ine. 
Palato-labial. 


BONES. 


197 


MAIN  TRUNK. 
Ophthalmic. 

Palato-labial. 


COLLATERAL. 

Muscular  of  the  eye, 
ciliary  and  lachry- 
mal. 


TERMINATION. 

Meniugeal  and  nasal 
branches. 

Anastomose  together, 
and  ramify  in  upper 
lip. 


BONES. 


CENTERS  OF  OSSIFICATION. 


Vertebrae,  two  princi- 
pal, and  five  or  six 
complimentary. 

Atlas,  six. 

Sacrum,  five  vertebrae. 

Occipital,  four. 

Parietal,  two. 

Frontal,  two. 

Sphenoid,  two. 

Ethmoid,  three. 

Temporal,  three. 

Bones  of  ear,  one. 

Supermaxillary,  one. 

Teeth,  one. 

Intermaxillary. 

Palate,  one. 

Pterygoid,  one. 

Zygomatic,  one. 

Lachrymal,  one. 


Nasal,  one. 
Turbinated,  one. 
Vomer,  one. 
Inferior  maxillary, 

two. 
Hyoid,  seven. 
Sternum,  six. 
Rib,  three. 
Scapula,  two. 
Humerus,  six. 
Radius,  three. 
Cubitus,  two. 
Carpus,  all  one  apiece. 
Principal  metacarpal, 

two. 
Small  metacarpal,  one. 
Os  suffraginis,  two. 
Os  coronce,  one. 
Os  pedis,  one. 


Sesamoid,  one. 
Navicular,  one. 
Ossa   innominata, 

three. 
Ilium,  two. 
Ischium,  two. 
Pubis,  one. 
Femur,  four. 
Tibia,  four. 
Fibula,  one. 
Patella,  one ;  Tarsus, 

one,  except  Os  cal- 

cis,  two. 
Principal    metatarsal, 

two. 
Small  metatarsal,  one. 
Phalanges,  one  apiece. 
Sesamoids,  one  apiece. 
Navicular,  one. 


i 


Webster  Family  Library  of  Veterinary  Medicine 
Cummings  School  of  Veterinary  Medicine  at 
Tufts  University 
200  Westboro  Road 
North  Grafton,  MA  01536 


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